Effects of diet composition on postprandial energy availability during weight loss maintenance (Walsh et al., 2013)
Now, we’re getting somewhere!
3 diets (carbs 10%, 40% or 60%; protein was higher in the lowest carb group). Four weeks. CROSSOVER.
Then a test meal which approximated the diet assignment. Total “energy availability” in the blood was approximated by measuring the calories in blood glucose, free fatty acids, and ketones.
They found a significantly lower energy availability after the low fat compared to low carb meal, and interestingly, this correlated with metabolic rate: more fuels in the blood = higher metabolic rate. Postprandial insulin levels likely mediated some of these effects:
None of this correlated with hunger, although higher metabolic rate may bode well; food intake was controlled in this study, but the metabolic rate differential may help delay/prevent weight regain in real life.
Fwiw, hunger levels don’t even always predict food intake (eg, Mattes 1990).
HERE’s your hangry study: High glycemic index foods, overeating, and obesity (Ludwig et al., 1999)
Low, medium, or high GI breakfasts in obese kids, then measure ad lib food intake at lunch. In this study, hangry prevailed (sort of) and the kids who had the high GI breakfast ate more at lunch:
And in this study, it did correlate with hunger and the blood glucose trough:
Interestingly, this study showed a protein-rich beverage suppressed postprandial ghrelin levels the most:
…however, “We found no significant effect of macronutrient type on the subjective VAS appetite measures.” As mentioned previously, hunger and satiety are complicated biological phenomena; can’t really pinpoint one single hormone or metabolite responsible.
50 grams of protein from either whey, tuna, turkey, or egg white. Whey stimulated insulin secretion, blood glucose fell, and “Mean energy intake at the ad libitum meal was significantly lower with the whey meal than with the tuna, egg and turkey meals.”