Whey and casein proteins differentially affect postprandial blood glucose and satiety mechanisms, with relevance for type 2 diabetes and obesity. Therefore, the purpose of this work was to investigate the effect of the casein-to-whey protein ratio and total protein concentration of milks consumed with cereal on postprandial blood glucose, appetite ratings, and subsequent food intake in a randomized, controlled, double-blinded study with healthy young adults (n = 32, 23.4 ± 3.1 yr, body mass index = 22.2 ± 2.5 kg/m). Fasted participants consumed milk (250 mL) with either 80:20 or 40:60 (modified) casein-to-whey protein ratios at commercially normal (3.1%, wt) or high protein (9.3%, wt) concentration, or control (water with whey permeate), each along with 2 servings of oat-based breakfast cereal. Blood glucose concentrations were determined from finger prick blood samples and appetite was assessed using visual analog scales. Participants consumed a measured ad libitum pizza lunch at 120 min and blood glucose determination and appetite assessment continued following the lunch meal (140-200 min) to observe the second meal effect. Pre-lunch (0-120 min) incremental area under the curve (iAUC) and mean change from baseline blood glucose were reduced with consumption of all milk treatments relative to control. However, we found no differences between all treatments on pre-lunch appetite change from baseline and total area under the curve (tAUC) or lunch meal food intake. In terms of protein concentration results, high protein (9.3%, wt) treatments contrasted to normal protein (3.1%, wt) treatments lowered blood glucose change from baseline and iAUC, and post-lunch appetite change from baseline and tAUC. Protein ratio showed a modest effect in that modified (40:60) protein ratio lowered pre-lunch blood glucose change from baseline but not iAUC, and normal (80:20) protein ratio lowered pre-lunch appetite change from baseline but not tAUC. Therefore, high-carbohydrate breakfast meals with increased protein concentration (9.3%, wt) could be a dietary strategy for the attenuation of blood glucose and improved satiety ratings after the second meal.

The effect of beverages commonly consumed by children in-between or with meals on short-term food intake (FI) and glycemic control has received little attention. Therefore, 2 experiments were conducted in 9- to 14-year-old children following a randomized repeated-measures design. Experiment 1 (n = 32) compared the effects of water (control) and isocaloric (130 kcal) amounts of 2% milk, chocolate milk, yogurt drink, and fruit punch on subjective appetite and FI. Experiment 2 (n = 20) compared the effects of isocaloric (130 kcal) amounts of 2% milk and fruit punch on subjective appetite, FI, and glycemic and appetite hormone responses. One serving of the beverages was given as a pre-meal drink at baseline (0 min) and a second serving 60 min later with an ad libitum pizza meal. Meal FI in experiment 1 was lower by 14% and 10%, respectively, after chocolate milk and yogurt drink (p < 0.001), but not milk, compared with water. Cumulative energy intake (beverages plus meal) was higher after caloric beverages than water. In experiment 2, no differences occurred in pre-meal but post-meal glucose was 83% higher in overweight/obese than normal-weight children (p = 0.02). Milk led to higher pre-meal glucagon-like peptide-1 and post-meal peptide tyrosine tyrosine (PYY) than fruit punch (p < 0.01) but insulin did not differ between treatments. In conclusion, dairy products consumed before and with a meal have more favourable effects on FI, appetite, and satiety hormones than a sugar-sweetened beverage, but all caloric beverages result in more cumulative calories than if water is the beverage.

The objective was to compare the effect of dairy and nondairy beverages when consumed with carbohydrate at breakfast on subjective appetite, food intake (FI), and postprandial glycemia (PPG) in healthy young adults. Twenty-six healthy males and females (13 males and 13 females; 23.0 ± 2.6 years; BMI: 22.3 ± 1.5 kg/m) participated in a randomized crossover study. They consumed nonisocaloric amounts (250 mL) of almond beverage, soy beverage, 1% fat milk, yogurt beverage, and water (control) with cereal and 120 min later, an ad libitum meal. Subjective appetite, PPG, and insulin were measured at baseline and at intervals before and after the meal at which FI was measured. Post-treatment blood glucose was lowest following soy beverage compared with all treatments but was not different from milk (p = 0.0002). There were no differences between any other treatments. However, over the first hour, PPG for all treatments was 27% lower compared with water (p < 0.0001). Milk and yogurt beverage led to the highest insulin concentrations post-treatment (p < 0.0001) but there were no differences between treatments postmeal. All treatments reduced appetite and led to lower FI at the meal compared with water, but FI was lower after milk compared with all treatments except yogurt beverage (p < 0.0001). Both dairy and nondairy beverages consumed with a high glycemic cereal at breakfast increased satiety and decreased FI compared with water with cereal. Despite higher carbohydrate content, all beverages led to similar or lower PPG than the water breakfast, but dairy beverages increased insulin more than nondairy beverages.

The objective was to compare the effect of liquid, semi-solid, and solid dairy products and a nondairy beverage when consumed with glycemic carbohydrate on subjective appetite, food intake (FI), and post-prandial glycemia (PPG) in healthy older adults. Thirty healthy men and women (14 males and 16 females; age: 64.6 ± 2.4 y; BMI: 25.6 ± 2.5 kg/m) participated in a randomized crossover study. Treatments were one of 250 mL of 2% fat milk and soy beverage, 175 g of 2% Greek yogurt, and 30 g of Cheddar cheese consumed as part of an isocaloric (380 kcal) meal with bread and jam. Water alone served as the energy-free control for subjective appetite. At 180 min after consumption, the participants were fed an ad libitum meal to measure FI. Subjective appetite, blood glucose, and insulin were measured at baseline and at intervals both before (post-treatment) and after the meal (postmeal). Cheese and yogurt resulted in lower post-treatment blood glucose than milk and soy beverage when consumed with carbohydrate (p < 0.0001), but no differences among any treatments were observed postmeal. Treatments led to similar insulin concentrations. Post-treatment appetite was lower than after the water control for all treatments but suppressed more by cheese and yogurt compared with milk (p < 0.0001). There were no differences in FI among treatments. Cheese and yogurt increase satiety and lower PPG more than milk or a soy beverage when consumed with carbohydrate.

Intake of a mixed glucose/protein beverage acutely decreases T levels in overweight and obese peripubertal boys. A potential mechanism for this decrease may be secondary to an acute decrease in LH, but this requires further evaluation.