The purpose of this study is to determine energy expenditure and sleep in response to protein/carbohydrate and fat ratio of the diet over a short-term and long-term period of time.

The prevalence of obesity has increased worldwide to epidemic proportions. For long-term treatment success permanent lifestyle changes are necessary with regard to approach to food, physical activity patterns and behavior to emotional stress. Moreover, an association has been shown between sleep disturbance and obesity. Weight loss strategies regarding food intake regulation mainly focused on changing patterns of fat and carbohydrate consumption during the last decades. The role of protein has largely been ignored. However, protein has been observed to increase satiety and energy expenditure to a greater extent than carbohydrate and fat and can therefore reduce energy intake. However, it still has to be confirmed if this effect is permanent or transient over a longer period of time. Moreover, dietary intakes may significantly affect sleep when macronutrient intakes are manipulated. Since sleep deprivation has been recognized as a risk factor for obesity, improving sleep by a change in macronutrient intake would be promising in the treatment of obesity.

Inclusion Criteria:

• healthy
• age between 18-35 years
• BMI 18-27 kg/m2
• non-smoking
• weight stable (weight change < 3 kg during the last 6 months)
• no sleeping problems
• not using a more than moderate amount of alcohol (> 10 consumptions/wk)
• not using medication or supplements except for oral contraceptives in women

Exclusion Criteria:

• not healthy
• do not meet the criteria for BMI and age
• smoking
• not being weight stable
• using medication or supplements except for oral contraceptives in women
• sleeping problems
• using a more than moderate alcohol consumption
• pregnant or lactating
• allergic for the used food items