nighttime macronutrient choice and combined resistance and high-intensity interval training

Conditions: Obesity

Summary: obesity is recognized as a major public health concern because of its link to potential fatal complications arising from metabolic and cardiovascular diseases. despite many pharmacological advances in this field, lifestyle strategies that emphasize proper nutrient intake and physical activity continue to be the primary strategy for individuals to fight obesity. however, controversy exists regarding the type and timing of exercise and specific nutrient intake to maximize fat loss, muscle gain, and beneficial cardio-metabolic adaptations derived from these lifestyle interventions. furthermore, limited data exists investigating the impact of nutrient timing at times other than immediately before or after exercise and no studies have examined time-of-day nutritional intake in overweight or obese individuals.in addition, many individuals attempting to improve body composition and cardio-metabolic health are concerned with what food choices are appropriate in the late evening to support positive physiological adaptations. however, research-based information examining this topic is scarce. the investigators hypothesize that consumption of a protein beverage in the late evening before sleep will improve body composition, cardio-metabolic health, and adaptations to exercise more than an isocaloric placebo beverage. the investigators also hypothesize that the different digestion and absorption kinetics of whey and casein proteins will elicit different effects on the measures variables.

the purpose of this study is to examine the effect of consumption of a protein beverage in the late evening before sleep along with the combination of resistance and high-intensity interval training on improving body composition, muscle strength and overall health compared to a carbohydrate placebo beverage in overweight and obese individuals. specifically, we will be measuring heart rate, blood pressure, body composition, resting metabolism, maximal strength,cardiovascular function, hormones levels, blood lipid profile, appetite, mood state, and dietary intake. specific aims of the study are: to determine if acute ingestion of a liquid ready-to-drink protein supplement (30g whey or casein protein per serving) consumed in the late evening before sleep will alter the physiological milieu to favor anabolism and alter lipolysis and fat oxidation more than the carbohydrate placebo (34g of maltodextrin per serving). to determine if 4 weeks of daily protein supplementation (same supplement as above) in the late evening along with 3 days of exercise training per week will improve body composition, blood lipid profile, strength, cardiovascular risk profile more than a placebo beverage.

Eligibility criteria:
inclusion criteria: * healthy men and women * sedentary(exercises \<2 days per week for more than 40 minutes per session within the past 6 months) * overweight or obese (bmi ≥ 25) exclusion criteria: * those that exercise for more than 2 days per week for more than 40 minutes per session (within the past 6 months), * those that have uncontrolled hypertension (blood pressure (bp)\>160/100 mmhg) * those that take bp medications * those diagnosed cardiovascular disease * those diagnosed with stroke * those diagnosed with diabetes * those diagnosed with thyroid dysfunction * those diagnosed with kidney dysfunction * those with any musculoskeletal complications that would impede exercise * those that smoke heavily (\>20 cigarettes per day) * those that take cholesterol medication * those that take nutritional supplements (except for a multivitamin) * those with any allergies to milk products

Keywords: protein metabolism nighttime eating exercise training