We keep forgetting it, but eating lots and lots of protein won’t do a thing to negatively affect your body fat levels. Here’s why.
I’ve been working my glutes a lot lately. It does seem to be, after all, the body part of the moment, and not just for women. Besides, I’d been neglecting them for too long. How could it be otherwise since the only time I really see the damn things is when I’m in Macy’s trying on a new pair of chinos and I’m lucky enough to nab the big dressing room with the 3-panel mirrors?
In any event, after a futile month, it struck me: I was still in my summer diet mode. I wasn’t eating enough to grow anything, let alone my wanna-be Instagram-worthy bootie.
You can’t build a house without bricks, right? And neither can you build a more muscular butt or muscular anything without extra protein. You also most likely need to take in calories above and beyond maintenance levels.
I’m embarrassed to say, though, that my thinking was outdated. I’d forgotten what I know to be true and instead fallen back on conventional dietary thinking, which is synopsized like this:
“Eating extra protein during times of carbs and energy sufficiency contributes to increased fat storage, not muscle growth.”
That is, after all, what nearly every dietitian will tell you, what nearly every nutrition textbook will tell you. But it’s hogwash. It’s poppycock. No, no, we need a stronger word to describe this nonsense; we need to combine hogwash and poppycock to get hogcock. That’s what it is.
Moreover, it’s probably that belief that’s to blame for so many people, including me in this instance, failing to make progress in the gym.
By trying to maintain a relatively low level of body fat, I had followed a maintenance or below maintenance number of calories and treated protein like just another macronutrient: one that must be reined in lest fatness ensue.
But the truth is, eating a lot of protein, even up to 5.5 times the recommended daily allowance, will not make you gain any additional fat, even if all that protein adds a ton of calories to your diet. Instead, it seems to have a protective effect against fat during periods of increased energy intake while also leading to additional muscle mass, provided circumstances are right.
We’ve known for some time that overfeeding carbohydrates and/or fat results in body comp changes that are different from overfeeding on protein. We’ve also known for some time that dietary protein appears to have a protective effect against fat gain during periods of overeating, but just how protective, we didn’t know.
Enter George Bray and his colleagues in 2012. They randomized subjects to partake in one of three diets: low protein (5%), normal protein (15%), or high protein (25%). Randomized subjects were then “force-fed” 140% of their maintenance calories – about an extra 1,000 calories for 8 weeks straight.
As far as grams of protein per group, that worked out to be around 47 grams for the low protein group; about 140 grams for the normal protein group; and around 230 grams for the high group.
Carbohydrate intake was kept at about 41-42% between the groups, while dietary fat ranged from 33% in the high protein group to 44% and 52% in the normal and low protein groups, respectively.
After doing their dual X-ray absorptiometry (DXA) magic, the scientists found that while all subjects gained approximately the same amount of fat (the high protein group gained a little less than the other two groups), the high protein group gained about 3 kilograms (approximately 6.6 pounds) of lean mass.
I know what you’re thinking: “Hey, all three groups gained the same amount of fat. Where’s this alleged protective effect of protein, Forrest?”
Slow down, Bubba. The participants in the study were not resistance-trained. Neither did they perform any exercise during the study. That extra 6.6 pounds of lean mass fell on them like manna from heaven. Clearly, their results showed that excess protein during an overeating phase contributed to lean body mass gains.
That throws a high-protein pie in the face of all those dietitians who still insist that a calorie is a calorie.
But what would happen if someone took it one step further? What would happen if someone conducted a similar study, but this time with resistance-trained athletes and an even higher protein intake?
Dr. Joey Antonio, a former contributor to T Nation, set about to “determine the effects of a very high protein diet (4.4 g/kg/d) on body composition in resistance-trained men and women.”
The study design was simple: Thirty healthy weightlifting men and women were randomly assigned to a control (CON) group or a high protein (HP) group. The CON group was instructed to maintain their same training and dietary habits over an 8-week period. The HP group was also instructed to maintain their same training and dietary habits (i.e., maintain the same carb and fat intake), albeit with the added instruction to take in 4.4 grams of protein per kilogram of body weight (about 5.5 times the RDA).
The math shows that the HP group would be ingesting around 800 calories per day more than the CON group. These additional calories were all from protein: 307 +/-69 grams of it, compared to a protein intake of 138 +/- 42 grams in the CON group.
Here’s the clincher: After 8 weeks, despite eating about 800 extra calories per day – all of it from protein – the HP group experienced no changes in body weight, fat mass, or fat-free mass.
You probably have mixed feelings about those results. On one hand, you’re probably elated that all those extra calories from protein didn’t result in any additional tubbiness. However, you’re probably disappointed that it didn’t lead to any additional muscle mass.
Read on for a clearer picture.
In the first study described above (Bray, et al.), the untrained subjects gained 6.6 pounds of lean mass just by increasing protein intake to about 230 grams per day. No exercise was involved, so this suggests that they weren’t getting enough protein to begin with, which casts dark aspersions on the U.S. recommended daily amount of protein (0.8 grams per kilogram, which would be about 63 grams for a 175-pound person).
That brings us to Antonio’s study: Why did the HP group, despite ingesting about 5.5 times the RDA for protein, fail to gain any lean mass, let alone fat mass? Antonio explained it this way:
“The lack of body composition changes in our group may be attributed to the fact that it’s very difficult for trained subjects to gain lean body mass and body weight in general without significant changes in their training program.”
So, it appears that the HP group simply wasn’t hitting it hard enough. Nowhere in the text does Antonio offer whether the resistance-trained athletes were just average gym goers in maintenance mode or mass-crazy gym rats, but you have to figure it’s the former, given what Antonio speculated later in the text:
“It would be interesting to ascertain if a high protein diet concurrent with a heavy resistance bodybuilding training regimen would affect body composition (i.e., increase lean body mass and lower fat mass).”
Admittedly, the title of this subsection is a little misleading. Protein can turn into body fat, but it’s unlikely. Biochemically, turning dietary fat into body fat is, as you might guess, easy-peasy, and turning dietary carbohydrate into body fat isn’t that much more difficult.
Turning protein into body fat, however, is an entirely different type of challenge. It takes several biochemical and hormonal steps and it’s monitored closely by the liver, which metes out amino acids according to the body’s metabolic needs (tissue breakdown, tissue synthesis, catabolism, anabolism, etc.)
As such, you can believe, with a high degree of certainty, that protein, despite what “common sense” might suggest, has a protective effect against fat gain in times of caloric surplus, particularly when combined with weightlifting.
All this might not be news to you, but it’s something that we need to be reminded of, because it’s so contrary to what we used to believe, or what many dietitians currently believe.
Having said that, here’s what I think you should take with you from these studies and this article:
- Regular, non-training Joes should probably throw the 0.8 grams of protein per kilogram RDA out the window and strive for at least 50% more.
- For most weight trainers who want to add muscle (but repeatedly fail), you likely need to eat more protein; maybe not 5.5 times the RDA, but maybe more than what you’ve previously believed to be adequate. The added calories will not turn to fat.
- Lastly, it’s probably impossible to eat that much extra protein from whole food sources, unless you routinely carry around a side of beef in your Yeti ice chest. You must, as the subjects in Antonio’s study did, augment whole-food protein choices with protein powder.
- Antonio J et al. The effects of consuming a high protein diet (4.4 g/kg/d) on body composition in resistance-trained individuals. J Int Soc Sports Nutr. 2014 May 12;11:19. PubMed.
- Leaf A et al. The Effects of Overfeeding on Body Composition: The Role of Macronutrient Composition – A Narrative Review. Int J Exerc Sci. 2017;10(8):1275-1296. PMC.
- Bray GA et al. Effect of protein overfeeding on energy expenditure measured in a metabolic chamber. Am J Clin Nutr. 2015;101(3):496-505. PubMed.