Using Protein to Improve Body Composition
Using meal replacement powders high in protein can have a beneficial
effect on body composition. In fact, the role of dietary protein in
body weight regulation has been recently examined by several investigators.
1-4 Protein plays a key role in food intake and body composition regulation
through its effects on satiety and diet-induced thermogenesis. It is
known that protein is more satiating than carbohydrate and fat in the
short term, over 24 hours and in the long term.4 For instance, one study
found that a high-protein weight-reduction diet may in the long term
have a more favorable cardiovascular risk profile than a low-protein
diet with similar weight reduction in people with type 2 diabetes.3
Certainly, there is a growing body of evidence that suggest the isocaloric
substitution of carbohydrate with protein produces favorable changes
in body composition; however, new evidence shows that consuming extra
protein after body weight loss may be an effective strategy in preventing
or limiting weight regain.
In a randomized parallel design, 148 male and female subjects (age 44
years; body mass index (BMI) 29.5 kg/m2; body fat 37 %) followed a very
low-energy diet (~500 kcal per day) during 4 weeks. For the next three
months of weight-maintenance assessment, they were stratified according
to age, BMI, body weight, restrained eating, and resting energy expenditure
(REE), and randomized over two groups. Only one group received 48.2
g/day additional protein to their diet. Measurements at baseline, after
weight loss, and after 3 months weight maintenance were body weight,
body composition, metabolic measurements, appetite profile, eating attitude,
and relevant blood parameters. They found that a 20% higher protein
intake, that is, 18% of energy versus 15% of energy during weight maintenance
after weight loss, resulted in a 50% lower body weight regain, only
consisting of fat-free mass. This was related to increased satiety and
decreased energy efficiency.2
Another similar study used a randomized parallel study design that consisted
of 113 overweight subjects (BMI 29 kg/m2; age 45 years) followed a very-low-energy
diet for 4 weeks, after which there was a 6-month period of weight maintenance.
During the weight maintenance period, subjects were randomly assigned
into either a protein group or a control group. The protein group received
30 g/d protein in addition to their own usual diet. The investigators
found that during weight maintenance, the protein group showed a higher
protein intake (18 % v. 15 % of calories), a lower weight regain, and
a decreased waist circumference compared with the control group. Weight
regain in the protein group consisted of only fat-free mass, whereas
the control group gained fat mass as well. Satiety in the fasted state
before breakfast increased significantly more in the protein group than
in the control group.1
In summary, it is evident that the mere addition of protein (~30-50
grams per day) may be an effective strategy in limiting weight regain.
Furthermore, any weight gain that may ensue is primarily fat-free mass.
The mechanism for this may include improved satiety, enhanced thermogenesis,
and greater energy inefficiency; furthermore, there are no deleterious
effects of the additional protein.4
References
1. Lejeune MP, Kovacs EM, Westerterp-Plantenga MS. Additional protein
intake limits weight regain after weight loss in humans. Br J Nutr.
Feb 2005;93(2):281-289.
2. Westerterp-Plantenga MS, Lejeune MP, Nijs I, van Ooijen M, Kovacs
EM. High protein intake sustains weight maintenance after body weight
loss in humans. Int J Obes Relat Metab Disord. Jan 2004;28(1):57-64.
3. Brinkworth GD, Noakes M, Parker B, Foster P, Clifton PM. Long-term
effects of advice to consume a high-protein, low-fat diet, rather than
a conventional weight-loss diet, in obese adults with type 2 diabetes:
one-year follow-up of a randomised trial. Diabetologia. Oct 2004;47(10):1677-1686.
4. Westerterp-Plantenga MS. The significance of protein in food intake
and body weight regulation. Curr Opin Clin Nutr Metab Care. Nov 2003;6(6):635-638.