Extended Evening Fasting: Metabolic Health and Energy Balance

The Effect of 4 Days of Extended Evening Fasting on Metabolic Health, Energy Balance and Appetite

This study will compare metabolic and feeding behaviour responses to 4 days of extended evening fasting vs. a control trial

Humans have evolved as a diurnal species, internally governed by the circadian system, which dictates our hormone regulation. 'Chrononutrition' is a sub-discipline which combines food timing with circadian physiology. The most popular method of time-restricted feeding in the UK is to skip breakfast. However, data from several meta-analysis have shown that skipping breakfast is associated with weight gain and insulin resistance, likely due to eating later into the evening/night and therefore, out of sync with our circadian rhythm. Recent research has shown that skipping dinner (evening fasting) has improved markers of cardio-metabolic health in clinical populations, although these are typically from longer-term studies. Despite these promising findings, it is not yet known whether these findings are population specific.

Therefore, the investigators are interested in examining the metabolic response pre and post intervention to see whether these promising findings can translate into a healthy population. Furthermore, the investigators will be monitoring subjective appetite, energy intake and expenditure to assess whether there is any short-term adaptation to a specific feeding window.

Inclusion Criteria:

• Non-smokers.

  • Have maintained a stable weight for 6 months (self-reported).
  • No history of gastric, digestive, cardiovascular or renal disease (self reported).
  • Female specific: must be using a monophasic, low dose combined OCP (containing less than 50μg oestradiol and a synthetic progestin) OR females with regular menstrual cycles (self-reported).

Exclusion Criteria:

• Severe food allergies, dislike or intolerance of study foods or drinks.

  • Currently undergoing a lifestyle intervention (structured diet or exercise)
  • Diagnosis of a condition or currently undergoing treatment therapy known to affect glucose or lipid metabolism (e.g., type-2 diabetes, taking statins), or contraindications to exercise.
  • Use of medication or supplements that may affect hormone concentrations.
  • Excessive alcohol consumption (>14 units/week).
  • Intensive training schedule (>10 hours/week).
  • Female specific: currently pregnant or breastfeeding, the use of any hormonal contraception, and the self-reporting of short (<24 d), long (>35 d), or irregular menstrual cycles.