Energy Balance is a crucial principle to understand before getting into the finer details of your metabolism.
Your Energy Balance represents the interplay between your total energy intake (diet) and your total energy expenditure (metabolism).
Think about Energy Balance like a counterbalance, seen in the picture. At any point in time, your Energy Balance can be in one of three states:
In general, Energy Balance is a strong predictor of body weight balance. Meaning a deficit is most likely going to lead to weight loss and a surplus is most likely going to lead to weight gain. I say "most likely" because some people might rightly point out that you can make a few tricky manipulations that will flip this logic on its head.
For example, consider the drastic level of carb cycling used by competitive bodybuilders or physique athletes in the weeks leading up to their show. Carbohydrates are stored in the body as glycogen, and every gram of stored glycogen binds up to four grams of water along with it.
In order to reach the insane level of aesthetic appeal required to come in first place, many competitors will continue eating the same amount of calories as they have been in previous weeks but completely eliminate carbs from their diet and substitute them with fats and protein.
You can store up to 15 grams of carbs per kilogram of bodyweight. If a competitor weighs 80 kilograms and decides to completely deplete their glycogen levels (which is really hard to do), they could theoretically lose up to six kilograms through glycogen and water loss. This would obviously show up on the scale as loss of body weight, but their body mass (fat or muscle) didn't actually change.
If a competitor properly depletes their glycogen levels, they set themselves up for a large rebound effect in the week leading up to their show, known as "Peak Week." Muscles that have very little glycogen to begin with can end up storing more glycogen when carbs are added back to the diet. This is known as "supercompensation." Exercise also contributes to this effect.
That same competitor, who now weights 74 kilograms, now reintroduces carbs to their diet in enormous quantities while nearly eliminating fat. This is known as "Carb Loading." According to the figures above, if they do it right, they can add up to 5.6 kilograms back to their scale weight while eating at maintenance or in a mild surplus. However, most of that glycogen will now show up in their muscles thanks to supercompensation, giving their muscles a much fuller look while still remaining as lean as possible. They'll be back up near 80 kilograms but appear drastically different.
The process of carb cycling is an illustration of how manipulating your intake of macros without changing your Energy Balance can lead to large changes in your scale weight while leaving your actual muscle and fat mass relatively unchanged.
Other caveats exist too. If you eat 1000 calories worth of broccoli for the next couple of days, you'd be in a huge deficit but your scale weight would probably go up just because you have so much food hanging around in your gut.
Try it... just kidding, don't. Really. Don't.
Save for a few tricks, Energy Balance is still a pretty strong predictor of weight change over time. But be careful: just because you're eating in a deficit doesn't mean you're losing fat, and just because your in a surplus doesn't mean you're gaining muscle.
You can gain fat in a deficit, lose fat in a surplus and you can stay weight-stable by gaining muscle and losing fat at the same time. In other words, you don't need to be in a surplus to build muscle or need to be in a deficit to lose fat (!!!). How you structure your diet, training and lifestyle will determine whether the body mass you add or lose will come from muscle or body fat.
Energy (Out Of) Balance
When people start gaining weight and blame their slow metabolism, they're actually saying that the amount of energy they're expending has been less than their level of energy intake for a considerable amount of time. As disgusting as it sounds, modern-day society caters to this exact situation.
Long gone are the days of lumberjacking and building railroads being the norm; most of us lead professions that have us strapped to a chair and fluttering away at a keyboard for eight hours a day. When you're done with your overly stressed work day, you've used up all of your willpower just to make it through the day and fall back on your instincts to guide your decisions. That likely means a pit stop at one of the 6,896 fast-food restaurants on your commute home.
Most any meal at any one of those restaurants can easily run you 1,000+ calories. By the time you're done with your meal, you're too swamped by blood glucose and cortisol to even think about going to the gym, and forget about having a quality night of sleep, that report is due by 6 AM tomorrow...
This might sound like a doomsday scenario, but it must be happening often enough in some form or fashion considering nearly 70% of the adult population in the United States is either overweight or obese.
It might sound tempting to blame mom and dad for the "slow metabolism" you inherited, and it is true that the genetics can explain up to 40% of the variance in your own metabolism. So at this point you have two options:
Who's on board for Option 2?
Before we can understand how to boost it, we have to understand what we're talking about when we refer to your metabolism in the first place. Many people believe it’s probably a cursed spirit living inside of you, sustained by the gluttony of meals at McDonalds in the past and hell-bent on making your clothes increasingly less comfortable.
In reality, we already noted that metabolic rate (total daily energy expenditure) makes up one side of your Energy Balance and is the compilation of a few key factors. I'm guessing most of you didn't get your bachelor's degree in Biomedical Science (don't feel bad, neither did I), so here's a helpful diagram:
The diagram above isn't just some laundry list of abstract concepts. The First Law of Thermodynamics states that energy cannot be destroyed, it can only change form. When we speak of diet and training, we're actually labeling forms of energy transfer: eating food transfers chemical energy, and objects in motion (a.k.a. humans and barbells) create kinetic energy.
It's a long-winded, nerdy way of saying that we can actually predict the numerical value of both sides of Energy Balance with a good amount of accuracy, including the three main factors of expenditure (Resting Metabolic Rate, Diet-Induced Thermogenesis & Physical Activity).
Resting (Basal) Metabolic Rate
The majority of your energy expenditure comes from your Resting (or Basal) Metabolic Rate, which is commonly abbreviated as BMR. Roughly 65% of your total expenditure is accounted for by the amount of energy it takes to keep your body functioning properly while at rest.
Even on those days where literally all you do is lounge around and watch Netflix, your body still requires a decent amount of energy (i.e. calories) to function. Fortunately, even the leanest of the lean still have thousands of calories worth of stored energy inside of their bodies that can fuel these functions in case we're even too lazy to get up out of bed and make some food.
While there are (at least) nine independent variables that affect your BMR, the most accurate predictive equations rely heavily on one in particular: lean, or "fat-free," body mass.
Different types of mass require different amounts of energy to be maintained. In 1992, Elia et al. proposed reference values (known as Ki) for the amount of energy required to sustain various different tissues, and these values have since been validated across genders and in populations under the age of 50 years old.
It can require up to three times as many calories to preserve a pound of muscle versus a pound of fat (6 kcal/lb vs 2 kcal/lb), which is why muscle mass has earned the distinction of being "energetically expensive".
And if muscle is "expensive," then organ tissue must be "baller status": it takes 200 kcal to preserve a pound of heart or kidney mass, roughly 110 kcal/lb for brain matter and just over 90 kcal/lb for the liver.
Last I checked, you can't exactly add a ton of brain or heart mass in the name of boosting your metabolism (I'll keep you posted on if this changes though). But these organs are very different from fat tissue in terms of energetic cost.
The most reliable formula we have to estimate BMR, the Katch-McArdle Equation, is based on measures of fat-free mass (FFM). This allows us to incorporate both organ mass, which is relatively "static," and muscle mass, which is relatively "plastic."
BMR = 370 + (21.6 * FFM in Kg)
To illustrate the impact of adding lean mass on BMR, let's look at a quick example:
Tim starts a strength training program at 220 lbs (100 kg) with 20% body fat. His BMR at this time:
BMR = 370 + (21.6 * 80 Kg FFM) = 370 + 1728 = 2098 kcal
Tim then optimizes his diet, training & lifestyle with the help of an awesome coach (shameless plug) and, six to seven months later, finds himself at the same weight of 220 lbs but is now down to 10% body fat. His BMR now:
BMR = 370 + (21.6 * 90 Kg FFM) = 370 + 1944 = 2314 kcal
Tl;dr - Tim boosted his metabolism by 216 calories per day by gaining muscle and losing fat (a.k.a. improving body composition).
Gaining muscle is a lot like "free cardio." Bodybuilders burn nearly 15% more energy at rest compared to an equally-lean control group. Keep this in mind for later.
Diet-Induced Thermogenesis (Thermic Effect of Food)
The second major component of your energy expenditure is Diet-Induced Thermogenesis, which is also called Thermic Effect of Food (TEF) in most of the research. This is the energy your body utilizes to metabolize the food that you just consumed.
Eating and digesting food does burn calories, but unfortunately no foods exist that burn more energy than they contain. Not even the latest drastically-overpriced superfood at your local health food store.
Even if you ate a diet completely consisting of celery (don't do that), you'd still end up taking in more calories than your body would utilize to process it. There's no such thing as "free foods."
The diagram above notes that this factor accounts for about 10% of your daily expenditure, but this value is geared towards people eating a standard Western (a.k.a. low quality) diet. This value can be pushed higher when you manipulate certain variables.
In 2010, Barr & Wright assessed the thermic response to a meal that contained the same calories but was composed of different foods. The meal totaled 730 calories; the "processed" version was a sandwich made of processed cheese (think Kraft Singles) and white bread, while the "whole" variation was the same sandwich made of multi-grain bread and cheddar.
After six hours, the "whole" group expended roughly 20% (137 kcal) of the meal's energy in response while the "processed" group only expended about 10% (73 kcal). The level of satiety from both meals was the same.
Even though multi-grain bread and cheddar cheese are less processed relative to the other junk, they're still inherently processed foods. It stands to reason that a meal consisting of truly whole foods (i.e. chicken and broccoli) would "cost" even more.
TEF also trends upward as you get leaner. Overweight individuals are shown to have a lower TEF in response to fat, and pre-diabetics/Type-2 diabetics who have poor insulin sensitivity have a reduced TEF in response to eating carbs.
In the Bayesian Bodybuilding PT Course, where I learned the information presented here, we're advised to push the estimate of TEF all the way up to 25% for lean individuals consuming whole-food mixed meals. Even this estimate may be conservative, but more research is needed to confirm this idea.
So let's use our pal Tim as an example again:
If he started his program at 20% body fat and ate your typical Western diet, his TEF would be close to 10%. If he was consuming about 2500 calories per day, this means he'd be burning about 250 calories in response.
Fast forward six months or so: if he eats the same amount of calories from whole foods at his new body fat percentage of 10%, he'd be burning 500 calories in response (if not more).
Tl;dr - Tim boosted his metabolism by another 250 calories per day by gaining muscle and losing fat (a.k.a. improving body composition).
The third major aspect of expenditure is Physical Activity, which is the most obvious way to increase your energy expenditure. When people find out about this, they jump to the conclusion that movement is movement, and they just have to "move more."
Newsflash: not all movement is created equal.
There are two considerations that define every type of movement:
Let's start with the easy one.
The amount of calories you burn doing any activity is going to be heavily based on the amount of time and intensity of the activity you choose to do. Here's a table comparing the calorie burn you'd experience doing common forms of exercise:
Time and intensity are inversely correlated, meaning the less intense an activity is, the longer you can do it and vice versa. So while it would be awesome to cycle at 25 mph for hours on end, I think that would break both the human body and the Laws of Physics.
A major consideration when implementing any type of exercise is that you will burn less energy doing any activity as you lose weight. This is why all of the calorie burn numbers in the diagram above are expressed in terms of calories/kg/min.
Hey, Tim? Can we use you again for an example?
If Tim still weighs 220 lbs, an hour of walking at 4.5 mph would burn 636 calories.
If Tim lost 20 lbs and now weighs 200 lbs, that same hour at the same speed would now burn 578 calories.
This is the Catch-22 with using most forms of exercise as the only means of losing weight: you're going to need to spend more and more time doing the activity just to burn the same amount of calories in order to lose the same amount of weight.
This is why long-term success requires a multi-faceted approach that includes routine training, proper diet and lifestyle modifications. While you might benefit a bit from each piece individually, the results you'll get from doing all three will be synergistic.
The second consideration is far more important: how your body adapts to different types of exercise in the long term. Any time your body is met with a stress, it adapts in a specific way to be better able to handle that stress in the future. For anyone familiar, this is known as the Specific Adaptations to Imposed Demands (SAID) principle.
All types of exercise are seen by your body as a stress; a positive one, but still a stress. Routine exposure to different types of stresses are going to signal very specific adaptations, which has led researchers to develop a theory known as the Strength-Endurance Continuum. This line of research has been around since the 1940's, so it's not exactly a well-kept secret.
If you'd like to take a deeper dive, Chris Beardsley of Strength and Conditioning Research wrote an excellent post exploring the origins and details of this theory. The main adaptations to either side of the continuum are summarized in the table below.
A review paper by Hawley (2009) highlighted the "Signaling Cascades" that result from different types of training.
Each different signal (type of exercise) leads to a different response (enzyme activation) that produces the intended adaptations (improvements). It's helpful to think of this process as a real cascade of water with two separate pools at the bottom; the enzymes up top guide which direction that water flows and how much each pool gets filled.
The entire point of this overly-nerdy explanation is that AMPk (AMP-activated protein kinase) and mTOR (mammalian target of rapamycin), the "master enzymes," aren't exactly friends. These two compete with each other to determine whether a cell grows (hypertrophies) or gets broken down for energy (catabolized).
As seen in the diagram, AMPk represses mTOR, and it doesn't even play nice with mTOR's pals: AMPk also blocks the signaling effect of Akt.
So when you do strength and endurance training in the same program, these enzymes literally compete with each other to determine what adaptations you will eventually end up with. You end up with far less water in each of the two pools at the bottom of the cascade.
This phenomenon is known as the Interference Effect. Training both ways hinders both forms of adaptation.
Considering how strongly your lean body mass impacts your metabolism, anyone looking to boost their metabolism and improve their body composition is best served to direct as much water into the "hypertrophy pool" as possible by choosing an activity that's going to activate mTOR.
"Couldn't I Just Eat Less?"
Now we have a much more concrete understanding of your metabolism. We know that gaining lean mass and improving your body composition will increase both your BMR and TEF, and that the type of exercise you choose is going to be a strong deciding factor in how much muscle you'll actually build.
But there's another side to Energy Balance that we haven't talked much about just yet, and that's your intake.
Unlike expenditure, intake is painfully straight-forward: the amount of calories you eat. Your state of Energy Balance relies on the relationship between intake and expenditure, and a deficit is probably going to allow you to lose weight.
At this point, many people think "well couldn't I just eat way less? Screw all those fancy acronyms."
And that's probably the worst idea you could possibly have.
Sure, you could create a huge deficit by dramatically cutting your calories. You might even have enough will-power stored up to last a few weeks using this approach and see some pretty drastic changes on the scale, which would seem like obvious validation.
But there are a whole lot of factors at work that will bring your progress to a screeching halt and leave your metabolism in the dust.
Just like exercise, your body views your diet as a stressor. By drastically cutting your calories, you create a huge deficit, and your body will start thinking that wold-wide famine just set in when you're really just trying to look good for beach season.
Being in such a negative energy balance destroys your hormone levels: IGF1, growth hormone and testosterone fall off a cliff while your cortisol, the "stress hormone," sky rockets. This is your body's way of telling you, "hey bro, find food. NOW."
As a result, your nutrient partitioning is thrown out of whack and you end up burning more of your lean mass, because at this point, your body is doing everything it can just to try to get back to homeostasis (or maintenance). As gruesome as it sounds, if you don't eat enough, your body would rather eat itself in order to survive.
There are also clear diminishing returns to reducing calories and weight loss: a review paper comparing super low calorie diets found no greater weight loss between groups consuming 420 vs 800 calories per day for six months.
Put another way: cutting your intake in half for half a year made no difference in weight loss.
Training of any kind would actually compound this problem. We already saw that the amount of calories you burn in response to activity decreases as you lose weight. As you continue to lose weight, your body motivates you to move even less to try to conserve the energy that it has left.
Not even strength training can save you at this point; even when studying athletes, a more aggressive deficit leads to more muscle loss and less fat loss than a more moderate deficit. Even though strength training is trying to send the signal to maintain your muscle mass, the signal from your diet to break down tissue for survival is so loud that it literally drowns it out.
This series of unfortunate events deserves its own novel called "The Murdered Metabolism" (10 points if you get the reference). The fitness industry is rife with people who have taken this approach. Jump on any online forum and you'll read dozens of stories about how people can't lose any more weight even though they're eating 500 calories a day. This led to the popular belief that crash-dieting created a lasting effect known as Metabolic Damage.
While I encourage you all to avoid the possibility of being in that position in the first place, I also want to reassure you that Metabolic Damage isn't actually a thing. There's no reason to believe that dieting once will destroy your metabolism forever. If that was really the case, then how do you explain bodybuilders who have been going through intense competition diets for months at a time year after year? You can't.
However, that's not to say your metabolism doesn't temporarily adapt to your current conditions. Researchers have used the term "Adaptive Thermogenesis" to explain this chain reaction that your body goes through in order to conserve energy in response to a deficit. This term explains "Yo-Yo Dieting" incredibly well.
On the far right of the graph above, you'll see an eight-week block of "Ad libitum" dieting. This means the subjects had no restrictions on what they could eat. Their energy intake went sky-high until they fully recovered their lean mass, which restored their hunger cues. But by that time, they had nearly 80% more body fat mass than when they began the experiment.
I hope it's painfully clear that when it comes to a deficit, more is not always better. This approach literally decreases all three facets of your metabolism by reducing your lean mass, reducing TEF and motivating less movement.
The Metabolic Blueprint
By now, we've teased out a few key points that are going to have major pay-offs when it comes to boosting your metabolism. We need to pick an activity that will allow us to maintain/gain lean mass in order to improve our body composition and optimize our BMR and TEF.
So let's take a look at how to do just that.
This should come as no surprise after reading about how much of an impact your lean body mass has on your BMR. Properly-structured strength training should be the cornerstone of anyone's fitness routine if their goal is to improve their body composition and metabolism in the long term.
We already know that utilizing strength training to get leaner will benefit your metabolism in a number of ways (if you don't by now, scroll up and reread everything), but there's another benefit laying in the weeds: creating new lean tissue costs a lot of energy.
That new muscle didn’t just appear out of thin air. Therefore, when gaining muscle mass, your metabolism will increase to accommodate this higher rate of energy being expended via tissue creation (anabolism).
It stands to reason that your metabolism will rise in unison with something known as your rate of Myofibrillar Protein Synthesis (MPS). This is just the fancy acronym way of saying "rate at which you can build muscle."
This rate of MPS rises much higher for much longer (up to 72 hours) in untrained individuals, which not only helps explain the "newbie gains" phenomenon, but also suggests that the beginning stages of your training career can provide the biggest boost to your metabolism.
Strength training is also one of the only ways to stay close to weight-stable on the scale while still losing body fat. Since the amount of energy you burn is directly correlated to your body weight, this means strength training is one of the only ways to maintain a higher "energy cost" of exercise.
Cardio, HIIT training, group classes, or basically any other type of exercise don't even come close to giving you these benefits. For more on the effects of these other types of training click here and here.
So if you're not strength training yet, start. And if you already are, I'll be coming out with more material on how to optimize training in the near future. In the meantime, check out this guest post I wrote for Supplement Reviews detailing why body-part splits are an ineffective strategy for most trainees past the beginner stage.
If you really want to take things to the next level with your training, you can just ask me ;)
As an added bonus, there also seems to be an optimal time of day to train: training in the evening will allow you to produce the most strength and recover the fastest, thanks to the activity being in line with your Circadian Rhythm. Sometime between the hours of 2:30 PM - 8:30 PM seem to be ideal, should you have the freedom to schedule your training time.
Optimize Protein & Fiber Intake
This should be another no-brainer based on what you learned earlier. Not only does TEF trend upwards as you get leaner, but the two biggest contributors to this value will be protein and fiber.
Protein has the distinction of being the most thermic macronutrient amongst the three (fat and carbs are the other two). When eaten in isolation, the thermic response to protein is close to 20% while the response to fats and carbs range anywhere from 0-15%.
But last I checked, most people don't eat nutrients in isolation; we eat foods that contain these nutrients. When lean individuals eat unprocessed foods that contain appropriate amounts of all three nutrients, the TEF of the meal comes closer to 25% (cited above).
This means that including all three macros with each meal will have the biggest impact on your TEF and therefore your metabolism. It appears that your body has a more favorable response when all of it's macronutrient friends show up to the party, so give your body what it wants.
Protein is also the only macronutrient of the bunch that can increase MPS all by itself. There is evidence that certain fats are also anabolic (promote the building of lean mass), but these effects appear to be additive. You can't expect to gain much muscle just by eating a bunch of olive oil.
Protein is the only macronutrient that contains amino acids, the building blocks of lean tissue in your body. High quality protein sources, such as dairy, eggs and animal meats contain all nine essential amino acids that must be derived from your diet as opposed to being made by your body.
All nine essential aminos (EAA) are... well, essential for muscle growth. However, a few specific amino acids have been found to have more pronounced effects on MPS.
You've likely heard of Branched Chain Amino Acids (BCAA), since nearly every supplement company in existence claims that these three amino acids are all you need in order to preserve muscle mass while cutting calories from your diet (since BCAAs in isolation contain less calories than an equal amount of whole protein).
One BCAA takes the anabolic crown, and that BCAA is leucine. This BCAA has been shown to independently activate mTOR in the human body. Take enough leucine, and the switch flips from off to on.
So is the answer just to swap out all of the protein in your diet for pure leucine powder?
Not only do BCAAs (including leucine) seem to be redundant and provide no benefit to your diet once you're already eating sufficient amounts of protein, BCAAs in isolation can actually decrease MPS.
I hate to break it to you, but all of the essential amino acids are essential for good reason. You might stimulate mTOR by taking in enough BCAAs or leucine, but even though the switch for MPS has been flipped "on," there's nothing there to provide the power. The other essential aminos are nowhere to be found, and since the switch has already been flipped, those aminos have to come from somewhere to support the increased rate of MPS.
Shocker: those other aminos are then broken down from your own body tissue to aid the cause. In my blog post on why BCAAs are useless, I noted how training in a fasted state in the morning has become a popular approach in the fitness community, and how that crowd has adopted the tactic of using a dose of BCAAs pre-workout to "stay fasted while preserving lean muscle."
While this is great in theory, when you take your BCAAs by themselves and then train your chest, you're actually breaking down another muscle group in your body to support the increased growth rate and training demand from the workout itself. You're basically borrowing from your quads to temporarily build your chest.
The key with protein, then, is to consume sufficient amounts of it from whole foods. 1.8 grams/kg (.82 g/lb) body weight per day appears to be a safe target for the vast majority of people. And no, purposely eating more protein won't provide any further benefit. More is not always better.
For our friend Tim, that's about 180 grams/day. For me, that amounts to just 143 grams at 175 lbs.
This level of intake will not only maximize your growth potential, but it will also maximize satiety (how full you feel throughout the day) thanks to something known as the "Protein Leverage Hypothesis." Unlike carbs or fats, protein can't be stored as easily by your body, and it's an important nutrient for a wide array of bodily functions (not just muscle growth). Accordingly, your body has a very direct sense of your level of protein intake, and your appetite will increase until a sufficient level (1.8 g/kg) of protein has been consumed.
When you're fully satiated, you experience less hunger throughout the day, which will keep you from running into that "doomsday scenario" I presented at the beginning of the article.
Contrary to popular belief, meal frequency has very little impact (if any) on your metabolism or fat loss. So "grazing" won't "stoke that metabolic fire," as I'm sure you've heard before.
In general, three or four meals per day will provide the best bang for your buck. These meals should come at consistent times across days to engrain your Circadian Rhythm, and proper care should be taken to surround your strength training with ample amounts of protein due to the increase in MPS you'll experience from it.
While leucine by itself isn't ideal, you need to make sure you're getting enough of it per meal to send the proper growth signal. This is called the Leucine Threshold. It's relatively easy to surpass this threshold at every meal by consuming at least .3 g/kg of high quality protein.
It's useful to know that the more processed a food is, the lower the protein quality and the less it can stimulate MPS. We already saw this to be the case with BCAA supplements.
As a rule of thumb, when considering how well a food can stimulate protein synthesis:
Whole Foods > Protein Shakes > Isolated Aminos
As an added bonus, both bracketing your training with higher amounts of protein and loading up on protein before bed can positively impact body composition and metabolism.
Next comes fiber intake, which is much more straight-forward in how it relates to TEF. The harder it is and longer it takes for the body to digest and harvest the energy from a meal, the higher the TEF.
Aside from being highly nutritious and having numerous health benefits, eating high-fiber foods can delay the time it takes for the food to pass through your stomach and also delay nutrient absorption. While this may sound like a bad thing, this means that eating adequate fiber will actually allow you to eat more food, since some of the nutrients you eat won't effectively be absorbed.
This is why the case can be made that fiber adds no calories to your diet; while it is a form of carbohydrate, it's not digested or utilized in nearly the same way as other carbs. Some forms of fiber can ferment in the gut, creating short-chain fatty acids that can contribute about two calories per gram to your intake. But once you balance this out against the minor blocking of nutrient absorption from the fiber intake itself, these values essentially cancel out.
As with protein, adequate fiber intake will also keep you much more satiated and allow you to stick to your targeted intake, since the number one reason diets fail is hunger. For males, the minimum daily intake of fiber should be close to 40 grams; for females, the minimum should be close to 25 grams. There's very little harm in exceeding this value, unless you're particularly sensitive to dietary fiber (and you'll know whether you are or not VERY quickly).
You may be wondering why I've been mentioning your Circadian Rhythm so many times. Menno Henselmans summarizes it like this:
Simply put, at different times of day your body is primed for different types of activities. When your biorhythm gets desynchronized from your daily agenda, your body does not function optimally. The results of this include a decreased metabolism, more cortisol production and less anabolic hormone production, lower insulin sensitivity, poorer recovery from exercise, a worse cholesterol profile, more hunger, impaired mental performance and lower sleep quality. Not to mention feeling worse. It’s not an understatement to say that practically everything you do benefits from a stable, synchronized circadian rhythm.
Knowing this, it's no surprise that the 2017 Nobel Prize in Physiology was awarded to three researchers working in this field of interest. This stuff matters. A lot.
So maintaining a high quantity and quality of sleep can provide plenty of benefits to your metabolism and body composition just by regulating your Circadian Rhythm.
Hormones like testosterone, growth hormone and leptin all have their own rhythms, and by getting enough sleep at a consistent time each night will allow you to ingrain these patterns and derive maximal benefit.
Take testosterone: the "alpha" hormone that is beneficial for muscle growth and body composition for both genders. As you can see, blood levels of testosterone are lowest around 10 PM and rise all the way until about 8 AM, with the levels being higher in younger adults than older adults.
Now... what's usually going on between 10 PM and 8 AM?
Growth hormone also tends to spike during sleeping hours while cortisol is at its low point. This makes sleep the most anabolic period of your day, bar none. Even if you have the greatest diet and training program in the world, you won't realize the proper adaptations without proper sleep.
Losing out on sleep impairs glucose tolerance and can potentially reduce leptin levels, which is an appetite-regulating hormone. In short: more leptin, less appetite. So conversely: less sleep, more appetite.
Just two consecutive nights of sleep restriction can increase ratings of appetite and hunger in healthy young males by nearly 25%. Restricting sleep to six hours, which many people claim they’re “lucky to get,” can increase calorie intake by 20% in just four nights. For most people, a 20% difference in intake makes the difference between being in a deficit or being at maintenance (or worse, being in a slight surplus).
Even if you somehow manage to keep your energy intake in check and maintain a deficit, don't expect to lose much fat while you're pulling all-nighters.
Nedeltcheva et al. (2010) compared the effects of a calorie deficit between a group sleeping 8.5 hours per night vs a group sleeping 5.5 hours per night. Both groups lost roughly three kg over the course of two weeks.
The group sleeping 8.5 hours lost 1.4 kg fat and 1.5 kg lean mass. The sleep deprived group lost .6 kg fat and 2.4 kg of lean mass. In other words, sleep deprivation cut fat loss by more than half while increasing the amount of lean mass loss by 60%.
You can bet your bottom dollar that these results would be even more favorable towards the full night sleep group if any type of training routine was put in place to help preserve lean mass.
Eight hours per night may be a good target for the general population, but athletes stand to benefit from even more.
In 2011, the Stanford Basketball team was put through a period of intentional sleep extension. Researchers took baseline measurements for certain skills like sprint performance, shooting percentage and reaction time during a two-week control period where the athletes slept on their "normal schedule." Then the team was instructed to get 10 hours of continuous sleep each night for the next two months.
By the end of the intervention, every measure of performance improved. They reduced their sprint time by .7 seconds, improved their free throw and three-point shooting percentage by 9% each and exhibited quicker reaction times based on the Psychomotor Vigilance Test (PVT). They also reported enhanced mood and well-being during the intervention.
Since strength training is a compilation of specific skills just like any other sport, these benefits should be seen for lifters as well. It also stands to reason that since athletes are putting more of a demand on their body on a daily basis that they'd require a longer period devoted to recovery (a.k.a. sleep).
What About Stimulants?
Instead of putting in the effort to make good habits that integrate all of the information above, most people end up turning to supplements to be the "magic pill" for their "slow metabolism."
The most commonly used stimulant in this regard, bar none, is caffeine. I'm not even going to mention some of the other more aggressive (and less legal) options...
Not only does this drug (yes, it's a drug) have addictive potential, its impact on energy expenditure depends on how "naive" you are to it in the first place. If you habitually consume coffee and energy drinks, your metabolism eventually becomes tolerant to these effects.
Maybe you find yourself in the perfect storm scenario, where you've never been a consumer of caffeine before and don't have any trace of an addictive personality. Even then, a dose of caffeine as high as 400 mg will only increase your rate of expenditure by about 32 calories for a few hours.
And spoiler alert: 400 mg exceeds the amount you need to stay under to remain intolerant, which appears to be around 100 mg. For all the info you'd ever care to know about caffeine, click here.
Not to mention that caffeine has a decently long half-life of about six hours. This means that every six hours after you've consumed caffeine, there will still be half of it in your system. Even if you have that short (not even a tall!) Starbucks coffee with 180 mg caffeine at 8 am, you’ll still have ~20 mg in your system at midnight. Let that sink in.
I hope I don’t need to tell you that having a CNS stimulant in your system is not conducive to good sleep. However, the detrimental effects on sleep seem to go beyond just having caffeine in your system in the first place. It appears that doses above the tolerance threshold may reduce the amount of time you spend in stages of deep sleep.
Caffeine also has a negative dose-response on your testosterone:cortisol ratio. This ratio is a marker for anabolism (muscle growth), and if you want to improve your body composition, you need to increase this ratio to favor testosterone. High-dose caffeine can therefore literally reduce your gainz.
Putting it All Together
Tim has been through a lot in this article already, but we're going to use him one more time to give an example of how optimizing his diet, training and sleep can impact his metabolic rate.
Remember, before starting his journey, Tim was 220 lbs, 20% body fat, consuming a generic diet, not training and had a sedentary office job. A.k.a. your Average Joe (I take offense to that remark, by the way).
By using an accurate calculator, we can plug this information in to get a targeted estimate of his maintenance intake.
Factoring in his BMR, TEF and activity level, Tim's daily energy expenditure is likely right around 2308 calories. This means he'd need to consume just about that much each day, or about 16,156 calories per week, to stay same as he already is.
Following six months of proper diet, exercise and lifestyle modifications, Tim stays at 220 lbs but is now 10% body fat, working out daily and is eating a diet entirely comprised of whole foods. His average daily intake now sits right around 3932 calories, or 27,524 calories per week.
In six months, Tim increased his level of maintenance intake by about 70%. Not a typo. 70%.
You might not be as big as Tim, carry as much body fat to start or even be a male, but this rationale holds for all people of all body types.
"Yeah, but this is just a theoretical example."
Well sure, so let's look at something more practical, like myself.
Earlier this year, I set out to prepare for a bodybuilding competition. While there were a few hurdles in the way that kept me from following all the way through, I was able to nail every facet (diet, training and lifestyle) down 100% for the first 12 weeks.
By the end of week 12, I was eating 954 more calories per day on average than I was at the start of my program, and I actually lost 4.5 lbs on the scale between those two points in time. This is the same type of effect that these changes can have on you.
Don't expect these changes to come overnight, though. In the example, it took Tim six months to reach these new heights. It took me nearly three months to see these type of results in myself. It takes consistent effort in proven principles.
It's also important to mention that in my personal example, a mild deficit was used to encourage simultaneous fat loss and muscle gain. This was also the implication in the example with Tim: there needs to be at least some period of time where you're eating a little less than maintenance in order to improve body composition.
For the average population, this should take the form of ~20% deficit, which would lead to about a 1% loss in scale weight per week. Anything more than that and you risk putting your lean mass on the chopping block. As you get even leaner, that deficit should shrink, and once you find yourself in the optimal range of body composition, you can switch things around to a surplus and gain lean mass much more effectively.
But if you put the right practices in place, even a deficit will probably end up being more food than you're already eating, since your energy expenditure is so much higher when you optimize your diet, training and lifestyle.
To illustrate this, I took the time to plot out what the full process for Tim would look like if he maintained the an optimal deficit for 10 weeks, followed by a mild surplus for the remaining 20 weeks. This would take him from 220 lbs at 20% all the way down to 199 lbs at 10% and then back up to 220 lbs at 10%. Being theoretical, we can afford to project what maximal progress would really look like in terms of increasing BMR and Energy Balance.
The orange line indicates Tim's target daily intake to encourage the desired changes to his body composition while training every day. As you can see, for the first 10 weeks, this value slightly decreases as he loses body weight, but it doesn't bottom out because he's maintaining lean mass. Even in a 20% deficit for 10 weeks, Tim is able to each way more calories per day than he would have otherwise; his maintenance level without diet or training is indicated by the dashed orange line below.
This value then skyrockets once Tim hit's his ideal body fat percentage of 10%. At that point, his intake flips from a 20% deficit to a mild 5% surplus, which would effectively limit any fat gain going forward and keep him at or near 10% body fat for the remainder of the program.
This illustrates the idea that even in a deficit, you can drastically improve your metabolism by implementing strength training and diet changes as opposed to doing nothing. Once you get into the optimal body composition range and earn the right to eat in a surplus, the numbers don't even compare.
Below the orange lines are blue lines representing his BMR. The solid blue line shows how his BMR would increase in a near-linear fashion for the entire 30 weeks, as he'd be gaining lean mass the entire time. The dashed BMR line represents the value where his BMR would have been had he changed nothing.
The same rationale applies: strength training, proper diet and proper lifestyle modifications are a sure fire way to boost every facet of your metabolism.
You're not resigned to living the rest of your life with a clunky metabolism. By making the proper changes to your diet, training and lifestyle, you can make drastic improvements to both your body composition and metabolic rate.
Once you know what to do, success is only a matter of time.
What would you do with an extra 70%?
The techniques, strategies, and suggestions expressed in this website are intended to be used for educational and entertainment purposes only. The author is not rendering medical advice of any kind, nor is this website intended to replace medical advice, nor to diagnose, prescribe or treat any disease, condition, illness or injury.