This link shows the importance of dietary protein in lean mass weight gain/loss and bodyfat accumulation/loss. You give two people the same number of extra calories to their diets; one with a high protein content, one with a low protein content. The person with the low protein excess calories gained significantly less weight than the high protein group. At the same time, the groups saw equal levels of bodyfat increases. Furthermore, the high protein group increased lean body mass, while the low protein group actually decreased this mass. And finally, the metabolic rates of the high protein group were significantly higher than the low group.
So even though two people may regularly eat the same number of, an excess, say, 1000 calories, to what is their normal “maintenance” level diet, the person who’s diet consists of a low-protein regimen will lose muscle mass while the person who’s diet consists of a high protein regimen will gain muscle mass. Additionally, the person who lost muscle will also gain just as much bodyfat as the person who actually gained muscle; while overall gaining less weight than the person eating a high protein excess in calories.
Anyway, interesting, but a pretty small scale study. 25 people? I also find it a bit confusing…the high protein group was consuming almost 1000 kcals a day more than the low protein group? Seems like it would have been more interesting to keep the calories the same, and just adjust the percentages of protein in the diet.
Renee, no. First they established what calorie maintenance was for each person on a diet of 15% of energy from protein, 25% from fat, and 60% from carbohydrates. Then they overfed each person by almost 1000 kCal/d keeping the absolute amount of carbs the same. One group got much more fat and had total protein kept to 6% of total calories with 52% coming from fat and 42% from carbohydrates (low protein); one kept 15% of energy coming from protein, with 44% from fat, and 41% from carbohydrates (normal protein); and one with 26% of energy from protein, 33% from fat, and 41% from carbohydrates (high protein). Note that since carbs were kept constant it would be just as fair to call the groups “high fat”, “normal fat”, and “low fat”.
And yes, the results showed that an overfeeding high fat/low protein diet resulted in a loss of lean body mass while gaining fat, whereas “normal” of each and low fat/high protein overfeeding still gained fat but also gained lean body mass.
Seems pretty unsurprising. High fat, high calorie, not enough protein, and you break down protein stores while storing the excess fat; enough to more than enough protein, still excess calories, and you increase both fat and protein stores. And?
BTW, similar findings are well established in “underfeeding” conditions. See here and here for example. Adequate (“high”) protein during calorie restriction, especially when coupled with resistance exercise, leads to preservation or gains in lean body (muscle) mass while losing fat mass, whereas not having enough protein will result in lean body mass loss along with fat loss.
It’s nice to see some solid evidence that seems to validate my personal opinion that it’s not just how MUCH you eat and how much/how you exercise, but also WHAT you eat, that influences your body comp.
There’s actually a fair amount of literature on this subject. My overall impression is that the main determinant of your body composition is how much you eat, but there are a bunch of other smaller effects that can add up to make a difference.
Well it all depends on how defines “main” and “smaller” I guess.
Type of activity. Someone who does a fair amount of resistance exercise, in the presence of adequate nutrition, is going to have more lean body mass; someone who does marathon training exclusively is not going to develop large amounts of muscle mass; a sedentary person is going to have less lean body mass yet. Is activity a “smaller effect”?
Macronutrient balance. Inadequate protein, both during overfeeding, and even more so in hypocaloric (weight loss) conditions will cause loss of lean body mass. Adequate protein with lowered calories and fat is lost while lean body mass is either preserved or increased. (Another example., And another.) Is this a small effect?
No doubt, “how much you eat” is a big part of it … but placing amount and sort of activity and macronutrient balance as “other smaller effects that can add up to make a difference” seems an odd statement to make. IMHO.
The significant finding was that a diet very low in protein (and high fat), down at 6% of energy from protein, will lead to loss of lean body mass. But there was no significant difference found in fat mass or lean body mass gain between the “normal” (15%) and “high” (26%) protein groups, which were also relatively “normal” and “low” fat respectively. Typical Americans may be lower in protein than is recommended by the US Department of Agriculture Food Guide, but the vast majority still are well above that “low protein” percent range.
One can therefore spin this study, in isolation, as showing no difference in weight gain and in body composition between between normal protein and high protein conditions, demonstrating that just eating a high protein diet alone, without limiting the absolute amount of calories, will not lead to any superior result than would eating a normal diet in the exact same amounts. “Good calories” alone is not enough.
The study, in isolation, also falsifies one common premise among the Atkin’s/low carb crowd: that it is the level of carbs that matters and that high fat is not bad, may even be beneficial. Carbs were kept constant and yet out outcomes varied based on the balance between fat and protein. The result can be parsed looking at how the fat content varied and demonstrating that high fat does matter in terms of adverse body composition*, and supporting the contention that a “low carb” diet should replace the carbs with lean protein, *not *with additional fat calories.
I suspect that the “fat is good” crowd will also “manage to find some way to justify their discredited belief.”
*The fact that there was no low carb condition, a natural objection, is immaterial to the issue of fat versus protein as the proposition that low carb matters is not being tested.
I agree. I suspect that the Atkins crowd will read this study and say that all of the groups ate the same proportion of carbohydrate and all three groups experienced similar levels of fat accumulation, therefore carbohydrate drives fat accumulation, not caloric intake. But since this study fixed both caloric intake and and carbohydrate intake we have no way of knowing which of these factors was responsible for fat gain.
Here are the two results I found most interesting:
The high-protein group had similar outcomes to the moderate-protein group, despite the fact that protein is known to have a huge Thermic Effect. No idea why.
With adequate protein intake, significant gains in Lean Body Mass can be achieved just by eating a lot. Strength training is not required.
No, it doesn’t have anything to do with that, because the mechanism is completely different. A low carbohydrate diet means eating so few carbohydrates that your body switches over to ketone bodies as the main energy source, with gluconeogenesis providing whatever situationally necessary carbohydrates that are not provided by intake. If you’re eating enough carbohydrates that your body doesn’t switch to ketosis, then it’s not even testing the same metabolic pathway.
The ceiling for protein intake is around 350–400 g. If you were eating an actual low-carb diet, you’d be shooting for 20–60 g of carbohydrate per day to maintain ketosis, and the remainder of your calories would be from fat; either stored body fat or fat from your diet. The limit on protein intake is how much your liver can convert. Eat too much, especially without enough fat to provide energy for the conversion, and you’ll get sick. So you can’t exclusively provide the bulk of your calories from protein, and if you’re maintaining ketosis you can’t eat more than about 60 g of carbohydrate (depending on the individual and the adaptation to fat metabolism, this may be even lower), so the bulk of your calories must come from fat. Again, the fat can come from stored body fat — which is where the higher rate of fat loss on a low-carbohydrate diet comes from — or from your food, but given a ketogenic state the necessary calories for protein conversion must come from fat.
All this study says is that given a fixed level of carbohydrate intake — which at 330 g per day is a significant intake; representing 60% of the calories in a 2,200 calorie diet — the proportion of fat and protein doesn’t make a significant difference in absolute weight gain, though it does affect body composition. This study addresses nothing in relation to a low-carb diet, nor does it say anything at all about the benefit or harm of high fat intake. It was a fairly well-designed study to test the hypothesis they wanted to address, but answers very few questions other than the one they focused on.
BBC Horizon did an episode on the Atkins diet in 04 and found that of all the claims it made the only thing that actually had any effect was the high protein portion of the diet, the more protein you eat, the less calories you need to eat was the short version of it.
Sleel, I was indeed careful to not state that this study falsifies the “low carb” diet plan or inform at all about the benefit or harm of low carb per se, but that it falsifies one premise held by quite a few of the low carb/Atkins acolytes - that high fat has no adverse consequences even in an overfeeding condition and may even be beneficial. Indeed the study authors designed the study to look at the effects of protein, but by necessity when carbs are held constant low protein equals high fat and high protein equals low fat. Under the condition of constant and putatively “normal” carbohydrate intake the only overfeeding condition that led to fat gain without any lean body mass gain was the high fat/low protein condition. If you want to claim that such a finding does not say “anything at all about the benefit or harm of high fat intake” … well … I honestly don’t know how to respond, anymore than I would know how to answer someone who claims that 2 plus 2 doesn’t equal 4.
What the … I would think they could go bad. I don’t know how comfortable I’d be eating something too long after its “Used best by …” date.
To return to this statement, actually there was the maintenance diet phase that had the same absolute level of carbohydrate as the overfeeding condition but had fewer total calories. That baseline was a 60% carbs condition with total calories such to have no weight gain or loss. Increase of calories with the same absolute amount of carbs was then associated with weight and fat gain. So we can say that increasing carbs did not drive the weight gain, calories did. And that low protein/high fat overfeeding prevented any of that weight gain associated with the increase in calories from being lean body mass increase.
I don’t think any pro-fat people will say that you can eat a diet high in both carbs and fat and not gain weight. The theory behind low-carb diets is basically that eating a lot of carbs, especially simple ones like sugar and flour, causes hormonal changes in the body that make fat storage easier, and also increases appetite so that you’re more likely to over-eat. So, yes, if you eat high-carb and high-fat, those extra calories are going to be stored, and you’re more likely to over-consume food in general. That says nothing about what happens on a low-carb, high-fat diet.
It’s also worth noting that although the participants in this study consumed an additional 53,000 Calories on average, they only added around 26,500 Calories worth of body fat and lean body mass on average (I assumed 1 lb. of lean body mass has 800 Calories).
For all three cases it would appear that the subjects’ bodies were only around 50% efficient at converting dietary calories into body mass.
