When people deliberately lose weight, usually what they are seeking to shed is excess fat. Unfortunately, evidence shows that a good proportion of any weight lost on a restrictive diet can come from muscle, and this is something that is generally best avoided. One thing that can help here is resistance exercise where the body is moved against a ‘load’ that can come from our own body weight (e.g. a press-up) or, say, a kettle bell, dumbbell, or elastic exercise band.
However, muscle contains a lot of protein, so theoretically eating more protein may help to preserve muscle during weight loss too.
This idea was tested in a study published recently in the FASEB journal [1]. In this study, 39 young adults were put on one of three diets that differed according to their protein content.
1. 0.8 g of protein per kg of body weight per day (the US recommended daily amount of protein)
2. 1.6 g of protein per kg of body weight per day
3. 2.4 g of protein per kg of body weight per day
For 10 days, the individuals ate the diet in amounts designed to maintainstable weight. Then for three weeks, calories were cut to induce a weight loss of about 2 lbs per week. All groups lost weight (an average loss of 3.2 kg over the 3 weeks).
However, the researchers did not just measure weight, but also the proportions of weight loss contributed by fat and muscle loss.
In groups 2. and 3. individuals lost more fat and less muscle than individuals in group 1. There was no significant difference between groups 2. and 3.
What this study shows is that the recommended daily amount of protein is probably generally inadequate for those seeking to optimise their fat loss and muscle maintenance during weight loss. Higher levels of protein appear to be better.
But, to my mind, there’s another major advantage of a diet perhaps a bit richer in protein. This relates to the fact that protein is, calorie for calorie, generally more satisfying than carbohydrate or fat. Diets that are relatively rich in protein generally make it easier for people to eat less but without undue hunger. This is important, because the absence of hunger is usually required for any dietary regime to be sustainable – and this is what helps assure long-term results.
Interestingly, other research has found higher-protein diets to be better for weight loss maintenance [2]. See here for more about this.
References:
1. Pasiakos SM, et al. Effects of high-protein diets on fat-free mass and muscle protein synthesis following weight loss: a randomized controlled trial. FASEB J September 2013 27:3837-3847
2. Meinert Larsen T, et al. Diets with High or Low Protein Content and Glycemic Index for Weight-Loss Maintenance. N Engl J Med 2010; 363:2102-2113
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Interesting data. Couple of questions:
1) Shouldn’t the protein level, whatever is optimal, be based on lean body weight? Me, I weigh 170, and if my Tabata scale is right (LOL, from what I read), I have 35 lbs of fat.
2) I have diminished kidney function, about 60%, according to estimated GFR calculations (creatinine is typically 1.3mg/dl). The nephrologists tell me to keep protein intake to .6 grams/kg of body weight, although I believe I’ve read studies that say CKD patients can do well on higher amounts of protein. What’s true here.
3) Some of us are doing ketogenic diets. Protein can push you out of ketosis, thus, in theory, making it more difficult to lose fat. Is timing of protein important? Like, after a workout.
Somewhat off topic, I’ve been using a terrific book, “Your body is your gym.” These are exercises based solely on the use of body weight (push ups, pulls ups, and a hundred more.
Full disclosure: I have no financial interest whatever in the author or his product.
These exercises give you a powerful workout of several muscle groups, and I have done them quite successfully before eating breakfast, with no apparent ill effects.
Some people who are interested in living longer have also read papers suggesting that mammals live longer on a protein-restricted diet, especially if it is low in methionine. See e.g. http://www.longecity.org/forum/topic/9303-life-span-extension-wmethionine-limiting-diet/.
It would be nice to be able to reconcile the evidence that more protein may be good for you with the evidence that more protein may be bad for you. Or perhaps just some amino acids are harmful. But methionine is quite abundant in most protein-rich foods except for legumes.
Many of the population may become healthier if they become thinner, which may be achieved by a low-carb.diet. But how to reconcile a diet lower in carbs. and one lower in methionine; is it possible?
Dr B., does not high/excess protein turn into glucose and potentially hyperglycemia? Would not fat be a better way to satiate?
It’s something bodybuilders have known for decades. When dieting before a contest protein stays high and carbs are cut. This helps them lose weight while holding onto muscle tissue.
It’s also one of the many benefits of the Atkins diet which can help to prevent the “skinny fat” look as people lose too much weight and muscle. Too many dieters can end up looking saggy and baggy if they don’t pay attention to their macro-nutrients.
What would you rather look like a tiger or bloated hippo?
Longer term studies on high protein diet have been disappointments. For some reason many obese struggle in modifing protein content of their diet, like in this 24 month study http://www.ncbi.nlm.nih.gov/pubmed/22286528
Hard to believe increasing protein would be a real game changer, but protein is surely satieting and helps in preserving muscle mass.
Why, on those dietetic experiments, is longevity a desirable aim? Obviously, enjoyment of life arises from being fit and healthy (at least to most of us) but living into advanced old age has its problems. A friend of mine is 101 years old and remarkably in good shape but is sad that she has been left behind and socially there is no one of her generation with whom she can identify socially. She suffers from loneliness but of an unusual form; that of not belonging to the generation into which she was born so psychologically longevity has its problems and probably should not be a desirable objective; good health, yes, but surely never longevity?
I really wonder what foods the diets included.
You probably know a drug called ractopamine used to increase muscle mass of livestock animals in U.S. and it probably mostly remains in the meat products because it is given to animals when the cutting time is very near. Maybe it’s this drug that made them lose less muscle and the drug also exerted harmful effects on them(Ractopamine is not for use in humans for any medical purposes and its effects on humans is unknown, and it is banned in 160 countries).
Whether or not ractopamine is a cause, what foods the diets included is still very important because you can not achieve a macronutrient change without a micronutrient change with only foods and it may also be the micronutrients that worked; but probably even more importantly, there are big differences between different proteins and their effects, and the same is true for carbohydrates and fats.
Hi Dr.Briffa,
I recently bought a copy of your book “Waist disposal: the ultimate….” and found it very interesting. As a scientific researcher myself i was especially interested in the myth debunking and scientific references. I have since started a low carb diet, sticking fairly close to the suggestions in the book with no more than 40-60g of carbs per day.
My goal is to develop tone and torso definition as i am not overweight and in the first week i droped from 11 stone 7 to 11 stone even. Its been nearly 2 months now and my weight is still 11 stone and i dont seem to be loosing mid rift weight. . . . .
My question is, what sort of timescale should i be looking at before i see reasonable results, weeks? months? I realise there is no straight answer here and many variables are involved . . .but in your experience for a moderately active guy is there a rough answer?
Most Kind regards
Colin