Evaluating the Intervention-Based Evidence Surrounding the Causal Role of Breakfast on Markers of Weight Management, with Specific Focus on Breakfast Composition and Size.

Nutritional strategies are vitally needed to aid in the management of obesity. Cross-sectional and epidemiologic studies consistently demonstrate that breakfast consumption is strongly associated with a healthy body weight. However, the intervention-based long-term evidence supporting a causal role of breakfast consumption is quite limited and appears to be influenced by several key dietary factors, such as dietary protein, fiber, and energy content. This article provides a comprehensive review of the intervention-based literature that examines the effects of breakfast consumption on markers of weight management and daily food intake. In addition, specific focus on the composition and size (i.e., energy content) of the breakfast meal is included. Overall, there is limited evidence supporting (or refuting) the daily consumption of breakfast for body weight management and daily food intake. In terms of whether the type of breakfast influences these outcomes, there is accumulating evidence supporting the consumption of increased dietary protein and fiber content at breakfast, as well as the consumption of more energy during the morning hours. However, the majority of the studies that manipulated breakfast composition and content did not control for habitual breakfast behaviors, nor did these studies include a breakfast-skipping control arm. Thus, it is unclear whether the addition of these types of breakfast plays a causal role in weight management. Future research, including large randomized controlled trials of longer-term (i.e., ≥6 mo) duration with a focus on key dietary factors, is critical to begin to assess whether breakfast recommendations are appropriate for the prevention and/or treatment of obesity.

A high-protein breakfast prevents body fat gain, through reductions in daily intake and hunger, in "Breakfast skipping" adolescents.

OBJECTIVE: The purpose of this study was to examine whether the daily consumption of normal-protein (NP) vs. high-protein (HP) breakfast meals improves appetite control, food intake, and body composition in "breakfast skipping" young people with overweight/obesity. METHODS: Fifty-seven adolescents (age: 19 ± 1 years; BMI: 29.7 ± 4.6 kg m(-2)) completed a 12-week randomized controlled trial in which the adolescents consumed either a 1,464 kJ NP breakfast (13 g protein) or a HP breakfast (35 g protein) or continued to skip breakfast (CON). Pre- and post-study appetite, food intake, body weight, and body composition were assessed. RESULTS: Time-by-group interactions (P < 0.05) were detected for body fat mass, daily intake, and perceived hunger. Specifically, HP prevented fat mass gains over the 12 weeks (-0.4 ± 0.5 kg) vs. CON (+1.6 ± 0.9 kg; P = 0.02), whereas NP did not (+0.3 ± 0.5 kg). HP led to reductions in daily intake (-1,724 ± 954 kJ) vs. CON (+1,556 ± 745 kJ; P = 0.03), whereas NP did not (+494 ± 213 kJ). Lastly, only the HP group experienced reductions in daily hunger vs. CON (P < 0.05). However, when directly comparing the HP vs. NP groups, no differences were detected in any outcomes. CONCLUSIONS: The daily addition of a HP breakfast improved indices of weight management as illustrated by the prevention of body fat gain, voluntary reductions in daily intake, and reductions in daily hunger in breakfast skipping adolescents with overweight/obesity.

Consuming High-Protein Soy Snacks Affects Appetite Control, Satiety, and Diet Quality in Young People and Influences Select Aspects of Mood and Cognition.

BACKGROUND: Data concerning the effects of afternoon snacking on ingestive behavior, mood, and cognition are limited. OBJECTIVE: The purpose of this study was to compare 1088 kJ of high-protein (HP) or high-fat (HF) afternoon snacks vs. no snacking on appetite, food intake, mood, and cognition in adolescents. METHODS: Thirty-one healthy adolescents (age: 17 ± 1 y) consumed the following afternoon snacks (in randomized order) for 3 d: HP snack (26 g of protein/6 g of fat per 27 g of carbohydrates), HF snack (4 g of protein/12 g of fat per 32 g of carbohydrates), and no snack (NoS). On day 4 of each treatment, the participants completed an 8-h testing day containing pre- and postsnack appetite questionnaires, food cue-stimulated functional MRI brain scans, mood, cognitive function, and eating initiation. Ad libitum dinner and evening snacks were provided and assessed. RESULTS: HP, but not HF, delayed eating initiation vs. NoS (P < 0.05). Both snacks reduced appetite vs. NoS (P < 0.001) with HP eliciting greater reductions than HF (P < 0.05). Only HF led to reductions in corticolimbic activation in brain regions controlling food motivation/reward vs. NoS (P < 0.01). Although no treatment differences in daily energy intake were detected, HP led to greater protein consumption than NoS (P < 0.05) and greater protein and lower fat consumption than HF (both, P < 0.05). HP led to fewer HF/high-sugar evening snacks than NoS (P < 0.01) and HF (P = 0.09). Although no treatment effects were detected for mood and cognition, HP tended to reduce confusion-bewilderment (P = 0.07) and increase cognitive flexibility (P = 0.09), whereas NoS reduced tension-anxiety (P < 0.05) and vigor-activity (P < 0.05). CONCLUSION: Afternoon snacking, particularly on HP soy foods, improves appetite, satiety, and diet quality in adolescents, while beneficially influencing aspects of mood and cognition. This trial was registered at clinicaltrials.gov as NCT01781286.

Effects of lactate consumption on blood bicarbonate levels and performance during high-intensity exercise.

The authors sought to determine the effects of oral lactate consumption on blood bicarbonate (HCO(3)-) levels, pH levels, and performance during high-intensity exercise on a cycle ergometer. Subjects (N = 11) were trained male and female cyclists. Time to exhaustion (TTE) and total work were measured during high-intensity exercise bouts 80 min after the consumption of 120 mg/kg body mass of lactate (L), an equal volume of placebo (PL), or no treatment (NT). Blood HCO(3)- increased significantly after ingestion of lactate (p < .05) but was not affected in PL or NT (p > .05). No changes in pH were observed as a result of treatment. TTE and total work during the performance test increased significantly by 17% in L compared with PL and NT (p = .02). No significant differences in TTE and total work were seen between the PL and NT protocols (p = .85). The authors conclude that consuming 120 mg/kg body mass of lactate increases HCO(3)- levels and increases exercise performance during high-intensity cycling ergometry to exhaustion.