In this YouTube talk, Ben Greenfield reviews a recent Strength and Conditioning Journal meta‑analysis that pooled 29 studies (≈729 resistance‑trained, non‑obese adults aged 18‑50) examining how dietary protein influences fat‑free mass (FFM) during calorie restriction. The analysis found a linear dose‑response: higher protein intake consistently preserved or even increased FFM while dieting. The crossover point where muscle loss stops occurs at ~1.9 g protein per kg body weight (≈0.85 g/lb), and benefits continue up to ~3.2 g/kg (≈1.45 g/lb). Each additional gram of protein yields a 0.06 effect‑size improvement with 99 % probability. Mechanistically, protein supplies nitrogen and activates leucine‑ and mTOR‑driven muscle protein synthesis, counteracting the increased muscle breakdown seen in lean individuals who have less fat as an energy buffer. Men show a stronger dose‑response than women (≈98‑99 % vs 80 % probability). The size of the calorie deficit (300 kcal up to >300 kcal) does not materially alter the protein requirement. Greenfield concludes with a practical recommendation: consume 0.85–1.45 g protein per lb body weight (≈1–1.5 g per lb for ease) during a deficit to preserve muscle and possibly gain lean mass.
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I was recently reading because I don't have a life and I do things like this for fun, the Strength and Conditioning Journal. The Strength and Conditioning Journal as a CSCS, I mean Certified Strength Conditioning Coach and Certified Personal Trainer through the National Strength and Conditioning Association. I still receive that journal. I've received it for 20 years and I actually read it usually in the bathtub. And this article was pretty cool. It was Basically, a look at what happens to fat-free mass, meaning all of the mass that is in you that is not fat, in energy-restricted, meaning people who were eating below their actual number of calories that they needed, resistance-trained individuals, right? So, these are trained people eating an energy-restricted diet. And, what they wanted to look at was, is there a certain ceiling or a certain amount of protein that can mitigate muscle loss and surprisingly even lead to muscle gain or fat-free mass gain even during significant calorie restriction. I realize that that seems to defy the laws of physics because calories in equals calories out. Yet multiple studies leading up to this point have shown that even if you are restricting calories, and in many cases if you are bedridden, not exercising, that protein intake can influence muscle protein synthesis in such a way that there's almost like this conservation of calories that allows for muscle maintenance and in some cases muscle gain. So, this is a new paper out in, like I mentioned, the Strength Conditioning Journal of August 2026 at the time that I'm recording this. And, it kind of updates, I think, some of the more cited protein recommendations in sports nutrition. So here's the background. In 2014, this researcher named Eric Helms and his colleagues put out this systematic review suggesting that lean— I'm lean, I fit into this category, which is why I was interested— resistance-trained, like people who weightlift, people who are in a calorie deficit actually need more protein than the general population. And they suggested something like 2.3 to 3.1 grams per kilogram of protein per day, grams per kilogram of your actual fat-free mass, not your total body weight. And don't worry, for those of you who prefer freedom units, I will express that in grams per pound later on as I go along. So that number has been repeated all over the place, 2.3 to 3.1 grams per kilogram of fat-free mass per day. So in freedom units, that's about 1 to 1.5 grams per pound of protein, grams per pound of protein, or grams per pound of protein based on what your fat-free mass is. So let's say you step on a body fat calculator or you do a DEXA scan or whatever, and you find out that you are— I don't know, let's just use a rough number because I suck at math. You're 100 pounds of fat-free mass. That would mean you're not a very big person, but you're 100 pounds of fat-free mass. Well, based on general recommendations leading up to this point, 1 to 1.5 grams per pound would mean that you would have 100 to 150 grams of protein per day. That would be the recommendation. So this new paper goes back and looks at 29 different studies over several hundred individuals, about 729 to be exact. And what they did was they pulled every study that exists out there that they could find, at least on people who lifted weights and people who were lean or at least non-obese, ranging from about 18 to 50 years old. And people who had gone through a period of calorie restriction that actually produced fat loss. And then they looked at what actually happened to their fat-free mass. Now, it's important here that when I say lean, it's all relative. Non-obese here means under about 28% body fat for men, underneath about 40% body fat for women. So they wanted people who didn't fit into the obese category. At least I wouldn't classify like, you know, a man at 28% or a woman at 40% body fat as lean per se, but they at least cut out folks who were obese and they looked at people who were trained and they screened over 900 studies and 29 actually made the cut. And what they wanted to run was a meta-analysis, right? Head-to-head comparisons based on studies that exist of high versus low protein groups. So they pooled all this data across 29 different studies and In short, what they found, in case you feel like hitting the fast-forward button, is that more protein intake tracks with better fat-free mass, which you could think of as like better muscle retention and in some cases muscle gain during a calorie deficit. And that relationship is linear, meaning that as protein intake increases, fat-free mass increases when you are dieting. So, What they actually found was the point where the data crosses from muscle loss to muscle maintenance or muscle gain was about 1.9 grams per kilogram of overall body mass per day. So that's about 0.85 grams per pound. And that's interesting because in the past, me and other guests I've had, perhaps most notably Gabriel Lyon, has talked about like around 0.8 grams per pound as being a pretty good amount of protein to target. on up from there versus what's normally recommended, which is around 0.55 grams per pound. Now, what they found was that every added gram of protein resulted in what's called a 0.06 effect size improvement with 99% probability. All of that means for you non-statisticians out there is that as you increase protein, your risk of losing muscle when you're on a calorie deficit continues to decrease as protein goes up. So, the top end of what they actually looked at, like the most amount of protein that they actually looked at, was about 3.2 grams per kilogram, which comes out to about 1.45 grams per pound of body weight per day. So, in summary, what that means is that if you're eating, if you're at a calorie deficit and you're eating 0.85 to 1.45 grams per pound of protein per day, We can say that all the way up to 1.45 grams per pound of protein, you're actually going to do a pretty good job staving off loss of muscle and possibly even gaining a little bit of muscle, even if you're dieting. So why is this? Well, a calorie deficit we already know suppresses muscle protein synthesis, aka MPS, if you want to sound cool. That's well established. So what happens to muscle breakdown depends on how lean you are. In people with more body fat, Breakdown tends to not occur as much during a calorie deficit, meaning the fatter you are, the less likely you are to lose muscle during a calorie deficit. And then in lean people, it's the opposite, as you would probably imagine. Muscle breakdown goes up, muscle protein synthesis goes down. Kind of a double whammy. And the reason for this is that if you're lean and if you're fasting or you're not consuming adequate calories, you excrete a bunch more nitrogen, like 2 to 3 times more nitrogen, and you burn more protein for fuel than people with higher body fat. Because fat mass is kind of the body's energy buffer. What that means is if you have less body fat, you have less energy buffer. So your body is going to turn to your own muscle tissue sooner because you just have less fat to burn. Now, dietary protein intake pushes back against that by giving the body an outside source of nitrogen and amino acids so it doesn't have to cannibalize muscle. And it can also prop up muscle protein synthesis through 2 different pathways, a leucine pathway and an mTOR pathway. So, the idea behind the increase in protein intake when you're on a calorie deficit has a few nuances to it. First of all, the leaner you are, the greater risk you have of losing muscle if you are at a calorie deficit. I question why you'd be on a calorie deficit anyways if you were lean, but I don't know, maybe you're doing it for the longevity, bro. You heard that fasting was good for extending longevity or increasing autophagy. So, every once in a while, you're doing a fast. Well, during those periods of time, if you're going to restrict calories, I would actually try to keep protein at least constant, right? Cut the calories from carbs, cut the calories from fat, but try to keep protein up because the leaner you are, the more a given gram of protein will do for you if you're at a calorie deficit and trying to maintain muscle. The next thing to know is that sex actually plays a role here. So men had about a 98 to 99% probability of a positive dose response to protein. Women They topped out at about 80%, right? So men seem to need— and I know there's a lot of female strength trainers and people who really endorse that females should eat adequate protein who aren't going to like that I'm saying this, but females have a little bit less of a need of higher protein compared to men when they're at a calorie deficit. But if I were you and I were a woman and I were listening in, I would play it safe and just still make sure that you're hitting somewhere around that 1 to 1.5 grams of protein. per pound of body weight, even if you are dieting. Now, the deficits didn't really seem to matter that much, meaning starting at 300 calories a day deficit on up to well over 300 calories per day still showed a need for higher protein intake, right? So whether you're dieting a little bit or whether you're dieting a lot, it's still a good idea to keep protein intake Pretty significant. So, the takeaway message for this entire discussion is basically this. If fat-free mass retention, AKA muscle retention, I guess fat-free mass, you could also classify some organ retention, like if you don't want your heart or your liver to get eaten away, data supports putting your protein intake at around 0.85 to 1.45 grams per pound of body weight. And, For me personally, just when you look at all the pooled data leading up to this point, I like to make that number easy to memorize, a little bit higher, and 1 to 1.5 grams per pound of protein. And, this latest study backs that up.
