Whey vs. Soy

[Guest guest]

This was just posted on the net on " Medscape Today " news. I thought it might be

of some interest to this group:

From WebMD Health News

Whey Protein May Be Helpful for Weight Loss

Goodman

July 15, 2011 — All protein may not be created equal when it comes to weight

loss.

Whey, or milk, protein may offer people who want to slim down a slight edge over

soy, a new study shows.

Researchers at the U.S. Department of Agriculture's Human Nutrition Research

Center randomly assigned 90 overweight and obese middle-aged adults to one of

three groups. The first group was asked to add protein drinks made with whey to

their normal diets, the second group drank protein drinks made with soy protein,

and the third group drank carbohydrate drinks.

Study participants weren't told which group they had been assigned to. All the

drinks, which were drunk twice daily, at breakfast and dinner, had the same

number of calories: 200. They also all had had 52 grams per packet, for a daily

total of 104 grams of added protein or carbs.

Researchers tracked participants' physical activity levels, weights, waist

sizes, lean and fat body mass, and blood levels of hormones related to hunger

and metabolism.

They also had people keep records of the other foods they were eating. The

researchers made sure participants were drinking the shakes during random urine

tests for levels of a chemical tracer they had added to the powders.

Seventy-three people completed the study, which is published in the Journal of

Nutrition.

Whey Protein vs. Soy Protein

When the study started, there were no significant differences between groups,

researchers report.

Men weighed an average of 218 pounds, while women weighed an average of about

190 pounds.

Throughout the study, all the groups ate roughly the same number of average

daily calories, about 2,200.

After six months, people drinking the carbohydrate shakes had gained a little

bit of weight, about 2 pounds, which appeared to be mainly added fat, compared

to where they started.

People drinking the soy shakes had stayed about the same weight as where they

started.

But people drinking the whey protein had lost a little bit of weight and body

fat, about 2 pounds. Additionally, while the other groups saw little change in

the size of their waists, the whey protein group lost about an inch around the

middle.

The study was partially funded by the dairy industry.

How Whey Protein May Affect Weight

Researchers say a couple of things may help to explain the weight and fat loss

seen with whey protein.

People in the whey protein group had significantly lower blood levels of the

hormone ghrelin than people eating the soy protein or carbohydrate.

" It's a hormone that helps regulate food intake, " says J. Baer, PhD,

research physiologist at the USDA's agriculture research service in Beltsville,

Md. " So the higher concentration, the more hungry somebody feels. The lower

concentration, the fuller somebody feels. "

And though researchers really can't explain why this happened or what it means,

they found that people drinking the whey protein had cut back on their

carbohydrate intake by the end of the study, even though they weren't eating

fewer total calories and didn't know what kind of supplement they were getting.

Though people drinking soy protein saw little change in their weight or body

composition during the study, they had higher levels of thyroid hormones

compared to those drinking whey. Thyroid hormones control metabolism and higher

levels may indicate a metabolic boost, though more research is needed to fully

explain what that may mean for weight loss.

For people who are hoping to replicate the results at home, researchers advise

picking a whey product that is also low in calories and fat.

" A lot of the whey products on the market also have a lot of calories in them, "

Baer says, " Consumers just need to read those labels. "

SOURCES:

Baer, D. The Journal of Nutrition, June 2011.

J. Baer, PhD, research physiologist, USDA agriculture research service,

Beltsville, Md.