Whey Protein Preserves MPS After Weight Loss

Protein is the new it ingredient. It’s making its way into all sorts of products—bars, drinks, bakery items and more. Earlier this month, we published our Survival Guide on protein, which explored protein fortification strategies and its role in functional foods and beverages. One thing is for sure, not only are there plant- and animal-based proteins to choose from, but which protein you select for your food or beverage application greatly impacts the final product in more ways than one.

One protein that’s popular in sports nutrition and weight management is whey protein. A new study published in The Journal of Nutrition examined the impact of protein quality (soy and whey) on the rates of myofibrillar protein synthesis (MPS) and lipolysis, processes that are important in the maintenance of muscle and loss of fat (Feb. 1, 2015).

A total of 19 men and 21 women, ages 35 to 65, completed a 14-day controlled hypoenergetic diet. Participants were randomly assigned, double blind, to receive twice-daily supplements of isolated whey (27 g) or soy (26g), providing a total protein intake of 1.3 ± 0.1 g/(kg /d) or isoenergetic carbohydrate (25 g of maltodextrin) resulting in a total protein intake of 0.7 ± 0.1 g/(kg/ d).

Pre-intervention, MPS was stimulated more (P<0.05) with ingestion of whey than with soy or carbohydrate. Post-intervention, post-absorptive MPS decreased similarly in all groups (all P<0.05). Postprandial MPS was reduced by 9 percent in the whey group, which was less than the reduction in soy and carbohydrate groups (28 percent and 31 percent, respectively) after the intervention. Lipolysis was suppressed during the postprandial period, but more so with ingestion of carbohydrate than soy or whey.

The researchers concluded whey-protein supplementation attenuated the decline in postprandial rates of MPS after weight loss, which may be of importance in the preservation of lean mass during longer-term weight loss interventions.

This study further positions whey protein as an ingredient that supports weight loss/management.