The Danish Food Administration recommends eating three main meals and three small meals a day in order to maintain a healthy lifestyle. However, there is little research to support this concept- moreover, many studies shows that fasting can have a positive impact on our health.

HYPOTHESIS AND PURPOSE The investigators hypothesize, that the number of meals per day in order to maintain a healthy lifestyle will not differ in normal weight subjects.

The investigators will include 1) healthy, normal weight subjects. The investigators will study the effects of two daily meals.

More specifically, the investigators want to better understand how the body reacts to long-term, intermittent fasting (14 h /day for 4 weeks). The investigators will assess cognitive function, dietary intake, appetite regulation, fitness, glucose and insulin responses, as well as fat and muscle composition of the body before, during, and after the study.

Our long-term goals are to compare the effects of intermittent fasting with acute fasting. All of this is in an effort to establish how our eating habits ultimately affect our health and to, perhaps, contribute to new recommendations for healthy eating in normal weight population.

BACKGROUND Obesity and diabetes are increasing health threats facing the Western world today, despite abundant research efforts and campaigns to prevent such outcomes. Throughout the years, as the incidence of both obesity and diabetes in the general population has increased, so too has the typical number of daily meals. A once common three meals per day has now increased to six meals per day, in many instances. Recent animal research has shown that intermittent fasting (one or two meals per day) over a long period of time can improve cardiovascular health and prevent chronic diseases. Biochemically, fasting leads to an activation of metabolic mechanisms designed to preserve carbohydrates and increase the dependence on energy produced by the metabolism of fat. There is little scientific evidence regarding the number of meals per day that proves to be the healthiest, and those studies that do exist have opposing conclusions. Several theories do exist regarding the number of meals per day that affect us in the most favorable way, but these are just theories. Our study is the first to assess, in both a systematic and controlled setting, how long-term, intermittent fasting affects the human body.

Inclusion Criteria:

• Physically active, defined as at least 8,000 steps per day
• Regular meal frequency, i.e. energy intake=energy utilized, and eating between 3-6 meals per day

Exclusion Criteria:

• Daily medications
• Acute illness within the past two weeks (infection, fever, or surgery)
• Chronic disease, including cancer, heart, liver, kidney, and respiratory diseases, as well as metabolic diseases, such as diabetes
• Alcohol abuse or more than 14/21 units (women/men) consumed per week
• Smoking, including occasional smoking