Weight loss supplements should include dietary protein. The questions are: how much of which proteins are the best? This recent study compares whey protein vs. soy protein.
Choosing Proteins for Weight Loss Supplements
Protein formulas for weight loss are usually limited to a few common sources: whey, soy, rice, pea, and egg white. All of these have their merits. Some commercial products mix two or more of them together. It is a challenge to evaluate them, however, because of the lack of research and the addition of numerous other ingredients whose effects just confound the impact of the proteins themselves.
In general, I have always sought protein formulas that contain little or no carbohydrate and no artificial or semi-synthetic sweeteners. These restrictions limit my choices to very few brands. Indeed, in my opinion, most of the protein formulas on the market are not worth buying. Many are downright lousy.
Nevertheless, those few brands that meet my stringent criteria provide proteins from different sources. Wouldn’t it be nice, I thought, to find some research comparing them in some way?
Example Research: Whey vs. Soy
This is exactly what I discovered when doing a recent search on PubMed for research on weight loss supplements. Keep in mind that scientific research is time-consuming, expensive, and limited to assessing only one or a few variables at a time. Nevertheless, we can glean some good information from a well-designed study.
Take a look at the abstract of the article below to see what I mean:
I got one of my answers, regarding how much protein to take, in the experimental design:
Ninety overweight and obese participants were randomly assigned to 1 of 3 treatment groups for 23 wk: 1) WP; 2) SP (each providing ~56 g/d of protein and 1670 kJ/d); or 3) an isoenergetic amount of CHO.
Most of the products that I use offer about 20-22 grams of protein per scoop. Now I know that, to get a clinical effect based on the above study, I should have two shakes per day, with at least at least 1.25 scoops each.
As for results, this looks interesting:
After 23 wk, body weight and composition did not differ between the groups consuming the SP and WP or between SP and CHO; however, body weight and fat mass of the group consuming the WP were lower by 1.8 kg (P < 0.006) and 2.3 kg (P < 0.005), respectively, than the group consuming CHO.
Translating into English, this means that whey protein had more of an effect than soy protein in comparison with a high-carbohydrate diet.
Now for all you statheads out there, the graphs are more explanatory than the numbers. I love graphs, don’t you? Here is what the comments in the abstract refer to:
Whey protein offers an advantage, based on this research. That is clear. However, even more so is the advantage that you get when you have more calories from protein and fewer from carbohydrate. You do have to be patient with expectations for results, though. You can see that the statistically significant changes among different treatments didn’t appear in this study until after about 5 months of the experiment.
Commenting on weight loss supplements,