Consistently working out on a regular basis translates, for some, into immediate, noticeable progress. The rest of us, however, are sooner or later confronted with the painful knowledge that sometimes the most rigorous exercise routines, the most popular nutrition plans, and a whole lot of willpower to put both into action are not enough to create visible change in either muscle growth or overall physical performance. Especially as we encounter a stubborn plateau, we come to wonder, what more can we do?
For many in this situation, the answer lies in a better understanding of their metabolism. Indeed, while trending training routines and dietary plans may work for some, they are usually extremely generic in the sense that they target only those people with a specific metabolic configuration. Naturally, they will not advertise this fact in headline font. In fact, they will commonly omit it altogether. So you pick up a popular set of reps and you religiously follow through with it. You eat a champion’s breakfast and concoct a nutrition-bomb smoothie before and after your workout sessions. You count every calorie you ingest. You do this for several weeks and, when you notice no progress, you understandably feel like throwing in the towel.
What I’m here to say, though, is that all hope is not lost.
Yes, training and physical exercise, together with a healthy diet, are essential for any increase in physical performance. However, metabolism is, in this case, the single most important process taking place in your body. Knowing your metabolism, therefore, is key to achieving more through your workout, regardless of whether you’re building muscle, training for a marathon or just staying fit. Following are the basics.
Metabolism and Physical Performance
Metabolism is so closely connected with both muscle growth and physical performance that they are virtually synonymous. In short, metabolism represents the sum of all chemical reactions taking place throughout the body, at a cellular level, for the purpose of providing energy and synthesizing new organic material. In the absence of metabolic processes, the body has no energy to sustain vital functions, let alone sustain physical activity. Furthermore, without metabolic processes, the synthesis of muscle tissue does not take place.1 It really is this simple.
But it does get more complicated from here. The human body relies on three main macronutrients for energy, and these are fat, protein, and carbohydrates. Of these, carbohydrates represent the body’s favorite source of fuel, which is to say that the body first turns to carbs in order to meet its energy needs. Once ingested, carbohydrates are broken down into basic components, such as glucose, galactose, and fructose. Glucose can be used as a fuel source for the brain and muscle tissue immediately, whereas the remaining two must first be metabolized into glucose by the liver. When sufficient carbs are ingested to create an excess of energy, the energy is stored as glycogen. If glycogen stores are also full, excess glucose is oxidized and stored as fat.
So what exactly happens when you work out? During physical exercise, the body first calls on any glucose present in the bloodstream for energy. In sessions that last more than one or two hours, glucose is depleted and the body begins to use up its stores of glycogen. At most, however, the latter will provide the equivalent of 2000 calories, so what happens when glycogen is also depleted? This is the moment when the body shifts towards protein catabolism to sustain continued effort. In other words, it begins to break down muscle tissue for amino acids, which are, in turn, oxidized for fuel. Protein is directed away from its primary task, building muscle and connective tissue, and the long-term result is the loss of muscle mass. Obviously, this is bad.
Derived from this are two basic principles that you can take into account when analyzing the relation between your metabolism and physical performance:
- If your intake of carbohydrates is poor or insufficient and your body is not properly stacked on glycogen, protein catabolism will likely occur during extensive workout sessions.2 You may think and feel that you’re exhausting yourself each time, and your routine may be an excellent one for muscle growth, but the results will ultimately disappoint you. Not only will your body lack the necessary resources to build new muscle, but it will actually be forced to break down some of the existing muscle tissue in order to meet its own energy needs.
- In order to increase your lean body mass, your body requires protein, of course, but it also requires more energy than your daily energy expenditure.3 The latter varies greatly from person to person, and is derived from the sum of your resting metabolic rate (RMR or the energy your body consumes while idle, for vital functions) and your exercise energy expenditure. Once you have assessed both and calculated your 24-hour energy expenditure, you can devise a nutritional plan that either matches the total amount, if you are training for an endurance event, or that exceeds the total amount, if you intend to increase lean body mass.
For each metabolism, there are both exercise and dietary requirements that, when fulfilled, can help an athlete achieve better performances. For the purpose of this discussion, I will focus only on the relationship between diet, different metabolic rates, and physical performance. To see the above principles in action, we will first look at an average metabolic rate, followed by a slow metabolic rate and, finally, by a fast metabolism. In each case, I will also present several suggestions for an appropriate, performance-enhancing nutritional plan.
Nutritional Needs for the Average Metabolism
Once you’ve completed your metabolic assessment at a nearby clinic, a specialist will be able to indicate whether your metabolic rate or, more likely, your resting metabolic rate falls within average parameters. If so, that is great news. Most workout routines and diets should show results in your case, but even so, you should be aware of some general principles of nutrition, metabolism and performance.
Broadly speaking, in order to achieve optimal results from your workouts, your nutrition should include4:
Carbs that rank low on the GI (glycemic index) and will provide you with sustained energy, rather than a quick burst. Your aim, as an active individual with an average RMR, is to consume 40% of your total calorie intake as carbohydrates. Some examples include raw fruits and vegetables, whole-wheat breads, and high-fiber cereals.
An absolutely essential component for repairing and building muscle tissue. Your goal is to consume an average of 30% of your total calorie intake as protein. Some examples include turkey, chicken breast, and salmon or, for vegans and vegetarians, seitan products, tofu, lentils, chickpeas, and most varieties of beans.
Intake mono and poly-unsaturated fats, as opposed to saturated and trans fats. Ideally, you should consume an average of 20-30% of your total calorie intake as fats. Some examples of foods containing good fats are vegetable oils (olive or canola, for instance), a variety of nuts (almonds, peanuts, cashews), avocados, and peanut butter.
Plenty of Water
The importance of water cannot be overstated. Intensive workouts, unusual heat, and fluid loss through sweat all deplete the body of water. Without water, a number of vital functions can no longer be fulfilled correctly, which translates into inefficient training and a lesser athletic performance. Under normal circumstances, it is recommended that an adult drinks at least 8 glasses of water per day (about 2 liters). In addition to this, consider drinking 0.5 liters (2-3 glasses) one or two hours prior to your workout, as well as at least another 0.5 liters during workout.
Another thing to consider is the timing of your meals in relation to your workout sessions. Ideally, this involves three meals, one before, one during, and one post-workout, each with different roles in enhancing your performance.
Your pre-workout meal (2-3 hours prior) is designed to provide energy for your body, hydrate you, and help you preserve muscle mass. In other words, you’re looking to include a moderate amount of protein, a good handful of your favorite complex carb food, and a small amount of fat.
Your during-workout meal needs to keep you hydrated, provide your body with substances that can be used for immediate fuel, and help you prevent muscle loss. For obvious reasons, this meal is best served as a drink, which should include, per hour of exercise, 15 grams of protein and 30-45 grams of carbs, avoiding fat altogether. A good idea is to prepare a during-workout smoothie, using half a scoop of protein powder and your preferred source of carbs (ranging from sports drinks to bananas, oats, quinoa, blueberries, beetroot, or even beans). Don’t forget to also drink enough water in addition to consuming your shake.
Your post-workout meal (0-2 hours after) is meant to help you recover, rehydrate, and build muscle mass. As such, it should include a good amount of protein, a moderate amount of carbs, and a small amount of fat. Although some prefer to prepare a post-workout shake that they can consume immediately after exercise, it is debatable whether or not this is actually necessary. In fact, so long as you eat your meal no longer than two hours post-workout, this should prevent any unwanted muscle breakdown.
Bear in mind that all the figures above are essentially designed to support an average resting metabolic rate, as well as an average workout routine. Athletes and bodybuilders have somewhat different nutritional needs and require further personalized dietary plans. An endurance athlete, for instance, has much higher calorie and carbohydrates needs, while a bodybuilder requires additional protein in order to facilitate major muscle growth.
And what about those with metabolic rates that fall below or above the average? Read on.
If Your Metabolism Is Slow
If your metabolic rate was assessed below average, it’s important for you to understand that this is not necessarily bad news. In fact, metabolic rate alone is never the culprit for weight gain, and it certainly doesn’t represent an obstacle in terms of physical performance.5 Rather, it simply means that your body uses up fewer calories in order to maintain vital functions. Having this awareness and knowing exactly how much you need to eat is all you need to keep unwanted weight gain at bay and to become, or stay, fit.
In terms of what your nutrition should include, as well as your three workout meals, you must bear in mind that your body finds it more difficult to process carbs and that, in addition to this, you have lesser energy needs. Of course, if you’re looking to build muscle mass or increase endurance, you too will need to consume more calories than your total 24-hour energy expenditure, but unlike other metabolic types, you should only exceed the latter by a small amount.
More specifically, it’s a good idea to lower your intake of carbs to about 25% of your total calorie consumption and to eat most of your carbs after working out. In your case, it is all the more important to consume complex carbs that do not immediately spike your blood sugar, since, due to your slow metabolism, you are prone to a poor insulin sensitivity.
You’ll want to up your protein intake to about 35% of total calorie consumption, which you can distribute evenly throughout the three meals. This is important not only because protein is the building block for muscle tissue, but also due to its ability to temporarily boost the metabolism.
Don’t be afraid of fat, so long as it comes in mono and poly-unsaturated types. People with slow metabolic rates showed best results on a high protein and fat diet, so up your fat intake to about 30-40% of your total calorie consumption.
Finally, there are a few nutritional tricks you might consider in terms of speeding up your metabolism. For instance, did you know that water has been shown to temporarily increase metabolism by 24-30%? This is partly due to the fact that calories are immediately used in order to heat the water to body temperature. Drinking enough water is a great way to stay hydrated in the first place, and this makes it even better for those with lagging metabolisms. Coconut oil, cocoa, as well as tea and coffee in moderate amounts have also displayed metabolism-boosting properties.
Metabolism on the Fast Track to Nowhere?
Most people tend to think that a fast metabolism is a free ticket to a life without fitness-related worries. While it is true that, if your metabolic rate was assessed above average, you naturally consume more calories in a day and you rarely put on weight, this fact is a double-edged sword. Gaining muscle mass is precisely that—putting on a specific type of weight, and it can be difficult to do with a fast metabolism.6 Nevertheless, this is not an impossible task. As usual, it begins with a metabolic assessment and the knowledge of exactly how many calories your body uses per day for vital functions, as well as for physical effort.
The trick, in terms of your nutrition plan, is to eat well above your total 24-hour energy expenditure. In addition, since your body can easily manage carbohydrates, while carbs, in turn, can help you build up your energy reserves, these should take up the better part of your meals. As such, your carbs intake should measure up to 55% of your total calorie consumption.
When it comes to protein, a moderate 25% of your total calorie consumption is ideal. Of course, if your focus is to significantly accelerate muscle growth, you can and should increase your protein consumption to 30-35%.
As always, healthy fat is not something to be ignored in a comprehensive diet. Nevertheless, if your metabolism is fast, you’ll want to keep your fat intake low, at about 20% of your total calorie intake.
Finally, pre, during, and post-workout meals are all the more essential for you, especially when it comes to your carbohydrate consumption. Remember that if your body cannot support its own energy requirements with glucose and glycogen, it will resort to breaking down muscle tissue for protein. Since you are prone to consuming lots of energy, you are particularly vulnerable to protein catabolism. In fact, it may be the reason why you haven’t noticed any improvements in your muscle mass in spite of working out consistently.
As the possessor of a quick metabolic rate, you’ll soon notice that muscle growth and especially endurance training require you to do a lot of eating. In fact, it is generally recommended that you eat as many as five meals per day, which may, at first, seem daunting. You’ll also have to be extra-diligent with your gym sessions, as building muscle will require you to train with weights intensely and consistently. On the other hand, there is, of course, the bright side, for when others will be terrified of carbohydrate-dense foods, you will casually produce a cookie from your bag, eat it with satisfaction, and then return to your multi-joint compound mass building reps.
The Ultimate Takeaway
There is an indisputable link between your metabolism and your physical performance, which you may be able to mediate through an appropriate nutritional plan. If you have struggled to increase your muscle mass, lose weight, or improve your endurance in spite of eating “right” and working out consistently, then metabolism might be the answer to your problem. There is only one way to find out, and that is undergoing a metabolic assessment at a nearby clinic or gym.
As you’ll notice while further researching the process, there are a number of online calculators that claim to be able to produce your RMR or your 24-hour energy expenditure with only a few details about your body. The issue with these, however, is that, like trending workout routines and dietary plans, they are designed with the average metabolic rate and body type in mind. Chances are, the results will not apply to your particular situation, which is why, if you’re serious about increasing your athletic performance, you should find out your RMR from a reliable source.
With the metabolic assessment out of the way, you’ll be able to tailor both your workout routines and your nutrition to fit your personal needs for much more effective training.
1. Hans Kornberg, “Metabolism,” Encyclopaedia Britannica, 22 November 2017, accessed January 26, 2018.
2. Michael J. Rennie and Kevin D. Tipton, “Protein and Amino Acid Metabolism during and after Exercise abd the Effects of Nutrition“, Annual Review of Nutrition, vol. 20 (2000), accessed January 26, 2018.
3. NSCA Kinetic Select, “Sport Performance and Metabolic Rate“, National Strength and Conditioning Association, 2015, accessed January 25, 2018.
4. American Dietetic Association, “American College of Sports Medicine position stand. Nutrition and athletic performance“. Medicine and Science in Sports and Exercise, vol. 31, no. 3 (2009), accessed January 25, 2018.
5. Harvard Medical School, “Does Metabolism Matter in Weight Loss?” Harvard Health Publishing, July 2015, accessed January 26, 2018.
6. K. D. Tipton and R. R. Wolfe, “Exercise, protein metabolism, and muscle growth“, International Journal of Sport Nutrition and Exercise Metabolism, vol. 11, no. 1 (2001), accessed January 26, 2018.