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Another take on the study that shows a high protein diet leads to more weight gain


Well this study [ Effect of Dietary Protein Content on Weight Gain, Energy Expenditure, and Body Composition During Overeating] has had a lot of press recently, mostly under headlines such as this:

Calories, not protein, matter most for fat gain

For the current study, researchers led by Dr. George Bray from the Pennington Biomedical Research Center in Baton Rouge, Louisiana, recruited 25 young, healthy volunteers to live in their lab and eat a prescribed diet for two to three months.

During the first couple of weeks, the researchers tinkered with participants’ diets to determine exactly how many calories they needed to maintain their body weight.

Then, for eight weeks, they piled on about 1,000 extra calories to those daily diets. One-third of the participants were fed a standard diet with 15 percent of their calories coming from protein, while the others ate low- or high-protein diets with either five or 25 percent of calories from protein.

That worked out to volunteers eating an average of 47, 139 or 228 grams of protein per day.

Those diets made everyone gain weight, but not equally. The low-protein diet group put on about seven pounds per person, compared to 13 or 14 pounds in the normal- and high-protein groups.

But people in the low-protein group stored more than 90 percent of their extra calories as fat and lost body protein (muscle mass), while other participants gained both fat and healthier lean muscle, researchers reported in the Journal of the American Medical Association. So the groups all gained a similar amount of total excess fat.

Many people interpreted this study in the following way:

If you eat less protein when you overeat – you will end up gaining less weight – which is a good thing. They make no distinction about the type of weight gained, nor do they make any point about the difference in fat gain, between the groups.

Now many of us have taken a closer look at the study – including Dr John Briffa. I.e. looking not just at the total weight – but what makes up the weight gain. If we do that we see an entirely different picture.

[From Dr Briffa’s post] Calorie breakdown of the different diets by percentage of protein, carbohydrate and fat were as follows:

  • Low protein – 6:42:52
  • Medium protein – 14:41:44
  • High protein – 26:41:33

Essentially carbohydrate stayed the same, but the ratio of protein to carbohydrate changed.

Here are the actual changes in body composition on the 3 diets:

weight change lean mass change fat mass change
low protein +3.61 -0.70 +3.66
medium protein +6.05 +2.87 +3.45
high protein +6.51 +3.18 +3.44

So as you can see – the group that put on the most body fat was the low protein group. This point is completely neglected in most headlines.

Headlines are indeed deceiving – with today’s focus on weight gain or loss, and the twisted headlines, now everyone thinks that it may be really bad eating a higher protein diet – when in fact the study showed you could gain significant muscle tissue, and less fat than a low protein diet.

Another headline in Medline Plus actually described the study in a different (and to my mind more accurate light)

Extra Calories, Low Protein Are Culprits in Weight Gain

…Those who ate low-protein diets gained less weight than the other groups, but the quality of the weight gained was worse, as it came from an increase in body fat. In contrast, the high-protein diets led to changes in lean body mass and helped participants burn calories.

“Most people are overeating and for those people who are, they need to pay attention to what they are putting into their mouths,” said study co-author Leanne Redman, an assistant professor of endocrinology at Pennington Biomedical Research Center in Baton Rouge, La. “If you overeat a high-fat, low-protein diet, you may gain weight at a lower rate, but you are gaining more fat and losing more muscle.

…The make-up of the weight — lean muscle or fat — may be even more important than the number on the scale or body mass index, said Dr. David Heber, director of the Center for Human Nutrition at the University of California, Los Angeles, and co-author of an editorial accompanying the new study. “Calories count,” he said. He encourages a high-protein, low-fat diet that is rich in colorful fruits and vegetables. “We are talking about lean protein such as white-meat chicken, ocean fish, turkey, egg whites and certain protein powders. Protein is more satiating, and helps reduce appetite,” he explained.

In my opinion the take home point of this study is – if you are going to overeat (to gain weight) eat lots of protein – at least then you’ll gain a decent amount of lean body mass along with the extra fat.

Even an NZ University professor got the message wrong.

Even a University Professor in New Zealand has stated in a National Publication that a low protein diet is better than a high protein one as people gain less weight on it! Yes this I was shocked to see.

Dr Kate Scott in a letter (which Jamie pointed out) to the editor in New Zealand Listener, which was in response to an excellent article by Nutritionist Jennifer Bowden, on the importance of protein intake for weight loss. Losing weight in 2012

You see like the others Dr Scott has not bothered to look at the actual amount of fat gain in the study. If she had bothered, she would have made an entirely different statement – perhaps “a low protein high calorie diet leads to more fat gain (and loss of muscle mass) compared to a high protein diet with the same calories.”

Kate Scott also used this study to ‘prove’ that higher protein diets stop you losing weight. You simply cannot use a study where people are deliberately overfed in order to gain weight, to prove a point about weight loss. She is simply wrong, study after study has shown that a higher protein diet used for weight loss, maintains lean mass, gives superior appetite control, and in this way helps those who are overweight eat less and lose it more easily.

I decided to email Ms Scott, and put it to her that she misrepresented the study she quoted, here is part of her reply to me:

“The study groups differ little in the amount of body fat they put on. Where they differ is in the fact that the two higher protein groups put on additional kilos in muscle. It is still extra weight. Recall that the Listener article was about whether eating more protein would lead to greater weight loss than eating less protein. Clearly, according to that study, it does not.”

But I’m distracted!

What I actually wanted to look at when I started writing this post was the amount of protein per kg per day that allowed people to gain a remarkable 3 kg of lean mass in just 8 weeks!

So I’ve added some further information into the table:

So if you were to eat 47 gram protein per kg per day – you lose muscle mass. This by the way is close to the RDA 0.8 g per kg per day. At 2.33 grams per kg or 1 gram per pound – you gain mass on a high calorie diet. So the formula that many in the fitness world subscribe to, of not less than 1.0 gram per lb, seems to be a good guideline if you want to gain mass. However, if you also want to lose fat, excess calories as in this study would not be a great idea. I’d suggest around 100 grams of carbs a day for most people. Less that this and you will likely use some of the protein to meet glucose requirements.


  1. Very interesting. I am surprised though that people put on 3kg of lean mass just by eating more especially when living in the lab. Or did they have a gym facility there where they would spend their evenings rather than going to the pub?

  2. Nice work, Julianne.

    You really have to laugh at researchers like Dr Scott who put so much weight in epidemiology. That someone of her supposed calibre cannot distinguish between over-feeding and weight loss protocols, between lean mass weight (and the associated benefits) and fat weight (and the associated detriments), is laughable. Moreso when someone plays the authoritarian card to underscore their arguments… “This overfeeding study published in this prestigious nutrition journal reinforces my own personal feelings about weight gain and eating animals so therefore any research referred to in this article is meaningless”.

    Unfortunately for Dr Scott, epidemiology doesn’t trump basic biochemistry.

  3. Hello, I’m sorry if you got a random comment from me earlier. I was part way through a comment when I got jumped on by a 6 year old and wrote something like djgfiowhegv0p9ih3ob, then my browser closed….

    Anyway…. this study has made me smack my head with my hand several times. What about measurements? THAT would have been a relatively accurate way to see what was going on. The higher protein group would surely have shown less gain in SIZE, right?

    You’d think with the sophisticated measuring devices available now (BIA, DEXXA, BODPOD), they could report something more accurate.

    Great post. I love what you write.

    • The Body composition was measured using DEXA. In both groups that increased lean mass, resting and total energy expenditure also increased, but not however in the low protein group.
      Again this emphasises to me the importance of maintaining a good protein intake, especially if you are wanting to lose weight. Typically weight loss diets decrease all macronutrients, as they focus on calories alone, which is likely to result in lean mass loss and lowered resting energy expenditure.

      • Agreed. I meant, with the knowledge they had (all the above – increased lean mass, resting and total energy expenditure) it boggles the mind that the results were reported as they were and I wonder why ‘everyone’ – mainstream media and apparently intelligent academics – took that angle.

  4. Also, I have to say that 3kg in 8 weeks of gain in lean mass is kind of incredible and.. hard to believe. Even with a very exact program of training for lean gain and a targeted diet, I’d be happily surprised to see half that in someone I was training. Have you ever seen this sort of gain in lean mass?

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