Using the protein leverage hypothesis to understand socioeconomic variation in obesity.

OBJECTIVES: The protein leverage hypothesis (PLH) predicts that protein appetite will stimulate excess energy intake, and consequently obesity, when the proportion of protein in the diet is low. Experimental studies support the PLH, but whether protein leverage can be used to understand socioeconomic (SES) variation in obesity is unknown. The objective of this study was to test two hypotheses from the PLH under non-experimental conditions. Consistent with the PLH, we expect that (1) absolute protein intake will be similar across populations, here defined as SES groups and, (2) the proportion of protein in the diet will be inversely associated with energy intake. METHODS: This was a cross-sectional study conducted in a random sample of 135 low-, middle-, and high-SES women in Costa Rica. Anthropometry was used to calculate body mass index (BMI). Twenty-four-hour dietary recalls were used to measure dietary intake. RESULTS: The prevalence of obesity varied between low- (38.8%), middle- (43.9%), and high- (17.8%) SES women. Absolute protein intake was similar across low- (58.5 g), middle- (59.4 g), and high- (65.6 g) SES women (p = 0.12). Protein intake as a proportion of total energy intake was inversely associated with total energy intake only among middle- (r = -0.37, p = 0.02) and high- (r = -0.36, p = 0.01) SES women. CONCLUSIONS: Consistent with the PLH, absolute protein intake was similar across SES groups. The relationship between the proportion of protein in the diet and total energy intake should be studied further in the context of real world conditions that may influence protein leverage.

Impact evaluation of a healthy lifestyle intervention to reduce cardiovascular disease risk in health centers in San José, Costa Rica and Chiapas, Mexico.

BACKGROUND: Previous healthy lifestyle interventions based on the Salud para Su Corazón curriculum for Latinos in the United States, and a pilot study in Guatemala, demonstrated improvements in patient knowledge, behavior, and clinical outcomes for adults with hypertension. This article describes the implementation of a healthy lifestyle group education intervention at the primary care health center level in the capital cities of Costa Rica and Chiapas, Mexico for patients with hypertension and/or type 2 diabetes and presents impact evaluation results. METHODS: Six group education sessions were offered to participants at intervention health centers from November 2011 to December 2012 and participants were followed up for 8 months. The study used a prospective, longitudinal, nonequivalent pretest-posttest comparison group design, and was conducted in parallel in the two countries. Cognitive and behavioral outcome measures were knowledge, self-efficacy, stage-of-change, dietary behavior and physical activity. Clinical outcomes were: body mass index, systolic and diastolic blood pressure, and fasting blood glucose. Group by time differences were assessed using generalized estimating equation models, and a dose-response analysis was conducted for the intervention group. RESULTS: The average number of group education sessions attended in Chiapas was 4 (SD: 2.2) and in Costa Rica, 1.8 (SD: 2.0). In both settings, participation in the study declined by 8-month follow-up. In Costa Rica, intervention group participants showed significant improvements in systolic and diastolic blood pressure and borderline significant improvement for fasting glucose, and significant improvement in the stages-of-change measure vs. the comparison group. In Chiapas, the intervention group showed significant improvement in the stages-of-change measure in relation to the comparison group. Significant improvements were not observed for knowledge, self-efficacy, dietary behavior or physical activity. In Chiapas only, a significant dose-response relationship was observed for systolic and diastolic blood pressure. CONCLUSION: Group education interventions at health centers have the potential to improve stage-of-change activation, and may also improve clinical outcomes. In the future, it will be essential to dedicate resources to understand ways to reach a representative group of the patient population, tailor the intervention so that patients are engaged to participate, and consider the broader family and community context that influences patients' capacity to manage their condition.

Water consumption increases weight loss during a hypocaloric diet intervention in middle-aged and older adults.

Water consumption acutely reduces meal energy intake (EI) among middle-aged and older adults. Our objectives were to determine if premeal water consumption facilitates weight loss among overweight/obese middle-aged and older adults, and to determine if the ability of premeal water consumption to reduce meal EI is sustained after a 12-week period of increased water consumption. Adults (n = 48; 55-75 years, BMI 25-40 kg/m(2)) were assigned to one of two groups: (i) hypocaloric diet + 500 ml water prior to each daily meal (water group), or (ii) hypocaloric diet alone (nonwater group). At baseline and week 12, each participant underwent two ad libitum test meals: (i) no preload (NP), and (ii) 500 ml water preload (WP). Meal EI was assessed at each test meal and body weight was assessed weekly for 12 weeks. Weight loss was ~2 kg greater in the water group than in the nonwater group, and the water group (beta = -0.87, P < 0.001) showed a 44% greater decline in weight over the 12 weeks than the nonwater group (beta = -0.60, P < 0.001). Test meal EI was lower in the WP than NP condition at baseline, but not at week 12 (baseline: WP 498 +/- 25 kcal, NP 541 +/- 27 kcal, P = 0.009; 12-week: WP 480 +/- 25 kcal, NP 506 +/- 25 kcal, P = 0.069). Thus, when combined with a hypocaloric diet, consuming 500 ml water prior to each main meal leads to greater weight loss than a hypocaloric diet alone in middle-aged and older adults. This may be due in part to an acute reduction in meal EI following water ingestion.