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 . 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 .
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