High Protein Diets Prevent Loss Of Muscle Mass

This commentary is from our highly respected Dr. Stephan Chaney

In several of my previous

emails I have highlighted studies comparing the low fat

and low carb diet plans.

You may recall that by year 1 or 2 (depending on the

study) there wasn’t any significant differences in

weight loss between the two diets.

But, the really discouraging finding from all of those

studies was that 12 months later the patients had

gained back most of the weight that they had lost in

the first place – even when behavior modification was

included as part of the weight loss program.

Recent research has shown that loss of lean muscle mass

was probably at least partially responsible for the

dismal long term success of both the low carb and low

fat diets.

Traditional diets (both low fat and low carb) don’t

provide enough protein to prevent loss of muscle mass.

Once you’ve lost muscle mass your metabolic rate

decreases significantly.

And, if your metabolic rate is low, it becomes an

uphill battle to keep the weight off – even with the

best behavior modification strategies.

Exercise helps, but exercise alone can’t prevent the

loss of muscle mass if you’re not getting enough

protein from your diet.

So what if you focused on higher protein diets? Could

you prevent that loss of muscle mass?

The answer is a resounding YES!

I’ve told you about Dr. Layman’s ground-breaking study

showing that high protein weight loss diets providing

around 10-12 g of the branched chain amino acid leucine

actually preserve muscle mass.

This week I’m going to bring you up to date on his

latest studies.

You may recall that Dr. Layman compared a high protein,

low fat diet (40% carbohydrate, 30% protein, 30% fat)

with a traditional low fat diet (55% carbohydrate, 15%

protein, 30% fat)

(Layman et al, J. Nutr., 133:

411-417, 2003).

The high protein diet was designed to

provide 10-12 g of leucine/day, while the low fat diet

provided 2-3 g/day

(Layman & Walker, J. Nutr., 136:

319S-323S, 2006).

The initial study showed that the high protein/high

leucine diet:

– promoted retention of muscle mass and preferential

loss of fat mass compared to the low fat diet.

– gave greater satiety (less hunger) and more energy

than the low fat diet.

These results were very impressive, because this was

the very first weight loss diet that had been shown to

preserve muscle mass. However, Dr. Layman didn’t just

rest on his laurels.

The initial study involved just the diet alone, so he

followed up with a study to see what would happen when

you combined the diet with an exercise program.

That study showed that exercise also promoted retention

of muscle mass and loss of fat mass, and that the

effects of exercise and the high protein diet were

additive (Layman et al, J. Nutr., 135: 1903-1910,


In short, exercise makes a good diet even better. No

surprise there.

The initial study didn’t fully examine how the high

protein diet affected risk factors for heart disease

and diabetes, so he followed up with a study to look at

those risk factors (Lasker et al, Nutr. & Metab. 5:30

(November 7) 2008).

That study showed that the high protein diet:

– gave a greater reduction in triglyceride levels, a

greater increase in HDL levels and a greater reduction

in the triglyceride/HDL ratio than the low fat diet.

– gave improved insulin sensitivity (as measured by the

increase in blood sugar and insulin in response to a

test meal) compared to the low fat diet.

The low fat diet initially gave a greater reduction in

LDL cholesterol levels than the high protein diet, but

that effect had completely disappeared by 12 months.

In short, the high protein diet has all of the

metabolic benefits of the low carb diets, but without

the unhealthy fats!

Finally, the initial studies had been short term (10

weeks to four months) with relatively small groups, so

he followed up with a large, multi-center trial that

followed people on the high protein and low fat diets

for 12 months (Layman et al., 139: 514-521, 2009).

This study showed:

– All of the advantages of the high protein diet were

maintained for the full 12 months.

– A significantly higher number of participants were

able to stick with the high protein diet for the full

12 months because it filled them up and gave them more

energy than the low fat diet.

– A higher percentage of participants on the high

protein diet were able to lose a significant amount of

weight (>10%) and keep it off.

At this point, the data are pretty compelling.

If you want to loose weight:

– ignore all of those fad diets. They are not really

backed by solid clinical evidence.

-ignore the debate about low carb versus low fat. If

you’re not getting the protein you need, neither one is

likely to help you in the long run.

Look for a diet that is as close to the high protein,

high leucine diet that Dr. Layman has pioneered and

couple it with exercise and lifestyle changes for

optimal results.

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