Why Are High-Protein Diets Encouraged For Weight Loss?
Aren’t all calories the same? Or, another way of thinking would be: “Is 1 calorie obtained from protein the same as 1 calorie obtained from fat or carbohydrates?”.
Given that a plethora of studies have demonstrated that weight/fat loss and energy expenditure have increased with diets that are higher in protein (Binns, Gray, & Di Brezzo, 2015; French et al., 2017; Layman, 2004; Layman et al., 2005, 2009), does this prove that calories from protein are “superior” in comparison to those broken down from fats or carbohydrates?
To really deep-dive into this issue, we first have to establish that:
Weight-loss is only possible when a caloric deficit exists
What is a caloric deficit? Well, exactly what it means — when a person takes in less calories (Calories In) than they are expending (Calories Out). It is a state of energy balance. Since the “Calories In” part is pretty self-explanatory (you know, it’s just what you put into your mouth throughout the day… and night during those Netflix series binge-watching episodes), I’ll expand on the “Calories Out” portion.
If you’ve ever seen the term “TDEE” strewn on your favourite fitness Instagram posts and it confused the heck out of you because wtf is TDEE, and who doesn’t explain their acronyms?! No worries, because “TDEE” is simply short for “Total Daily Energy Expenditure” and consists of 4 basic components:
Basal Metabolic Rate (BMR)
Non Exercise Adaptive Thermogenesis (NEAT) & Non Exercise Physical Activity (NEPA)
Exercise Activity (EA)
Thermic Effect of Food (TEF)
Basal Metabolic Rate (BMR) — This is the amount of energy per unit time that you need to keep the body functioning at rest. Some of these essential processes include breathing, blood circulation, body temperature regulation, cell growth, contraction of muscles, etcetera. Your BMR contributes to roughly 60% of “Calories Out”/ TDEE. If you’re a very physically active person (maybe you hit the gym every day or you are a NINJA — please call me if you are a ninja, I’d like to know you 😉), your BMR will then contribute relatively lesser to your TDEE.
NEAT & NEPA (too long to type out, sorry!) — Good news for those who are extremely fidgety (yes, I’m looking at you and your shaking legs): NEAT is the amount of energy you spend doing unconscious little movements, which are not exercise, throughout the day. On the other, NEPA refers to walking, standing, and any voluntary, non-exercise activity. For pedantic reasons, NEAT is separated from NEPA — NEAT is unconscious, while NEPA is conscious. Since we’re not particular about the specific terming (right?), I’ll just refer to it as NEAT for the purposes of this article.
Exercise Activity (EA) — Um, exactly what it says: it’s the energy expended when you exercise. The exact number of calories burned at the end of the workout really depends on the duration and intensity of the exercise performed. Also, trust me based on personal experience, it’s not nearly as many as you’d like it to be. 😦
Thermic Effect of Food (TEF) — Just because you ate (let’s say) 3000 calories in a day, that doesn’t mean that you will “get” 3000 calories from whatever you’ve eaten. I don’t know if you see that as a good thing, but it turns out that it actually costs you energy to “extract” the energy from the food that you eat! Different foods require varying amounts of energy to be processed and digested. I know, by this time, you’re thinking: “Wtf… I came here to find out if calories are equal but all I’ve gotten till now are a bunch of acronyms? 🙁”. Okay, if there’s only one thing you take away from this article today, let is be this:
Foods higher in protein and fibre have a higher TEF
Read that again. And the following equations:
Energy Balance = Calories In — Calories Out
Calories Out (TDEE) = BMR + NEAT + Exercise + TEF
Since protein has a higher TEF, it makes sense that when calories are equated with the only difference being levels of protein in the diet, there would be greater TDEE, resulting in greater energy deficit (aka weight loss! Abs, anyone? 😋). Also, since protein has a satiating effect, it’s REALLY difficult to overeat. Anyone tried eating 400 grams of chicken breast in one meal? 😬
Alright, that’s all from me today — I really hope you’ve finally understood why high-protein diets are recommended for anyone seeking to lose weight or fat, and learnt something valuable you can share with another person from this article.
Till the next time — stay scientific,
Gene 💕
References:
Binns, A., Gray, M., & Di Brezzo, R. (2015). Thermic effect of food, exercise, and total energy expenditure in active females. Journal of Science and Medicine in Sport, 18(2), 204–208. https://doi.org/10.1016/j.jsams.2014.01.008
French, W. W., Dridi, S., Shouse, S. A., Wu, H., Hawley, A., Lee, S.-O., … Baum, J. I. (2017). A High-Protein Diet Reduces Weight Gain, Decreases Food Intake, Decreases Liver Fat Deposition, and Improves Markers of Muscle Metabolism in Obese Zucker Rats. Nutrients, 9(6). https://doi.org/10.3390/nu9060587
Layman, D. K. (2004). Protein quantity and quality at levels above the RDA improves adult weight loss. Journal of the American College of Nutrition, 23(6 Suppl), 631S-636S.
Layman, D. K., Evans, E., Baum, J. I., Seyler, J., Erickson, D. J., & Boileau, R. A. (2005). Dietary protein and exercise have additive effects on body composition during weight loss in adult women. The Journal of Nutrition, 135(8), 1903–1910. https://doi.org/10.1093/jn/135.8.1903
Layman, D. K., Evans, E. M., Erickson, D., Seyler, J., Weber, J., Bagshaw, D., … Kris-Etherton, P. (2009). A moderate-protein diet produces sustained weight loss and long-term changes in body composition and blood lipids in obese adults. The Journal of Nutrition, 139(3), 514–521. https://doi.org/10.3945/jn.108.099440
Thanks for reading! If you want an evidence-based approach to fitness and nutrition, start by learning how to estimate your daily protein requirements. You’ll like it — I promise!
