In addition to its ability to preserve and even build lean body mass during dieting, whey protein may offer other benefits for dieters.
Dutch researchers examined the effects of whey protein consumed at breakfast on subsequent diet-induced energy expenditure and satiety. Men and women consumed three breakfasts in random order that contained on average a little over 400 calories.
The control breakfast was whole milk yogurt consisting of 15%, 47% and 38% energy from protein (16g), carbs and fat. The second breakfast was an equal calorie but higher-protein meal including whey protein, which consisted of 41%, 47% and 12% energy from protein (42g), carbs and fat. The third breakfast was the same as the second except it included whey protein enriched with added alpha-lactalbumin beyond the naturally occurring levels found in whey.
Compared to the control breakfast, the two high protein breakfasts with whey and whey rich in alpha-lactalbumin resulted in increased thermogenesis (21% and 30% respectively) during the four hour period after the meal. In addition, hunger and desire to eat were suppressed to a greater degree after the meal containing whey alpha-lactalbumin.
These findings provide evidence that a breakfast with whey protein promotes increased energy expenditure compared to a lower protein breakfast. The fast rise in leucine levels found in whey may be the key to increasing thermogenesis and decreasing hunger.