Four Weeks of Acute Intermittent Fasting Enhances Body Composition and Decreases Stress Levels in Healthy Individuals: A Pilot Study

Introduction The obesity epidemic affects nearly 78 million adults in the United States. Weight loss and improvement of body composition through physical activity and dietary modifications, can help decrease the risk for obesity‐related disease. Weight management programs are numerous, with an estimated 45 million Americans undertaking a diet each year. There are several different types of diets: such as those that emphasize consumption or an increase/decrease in protein, carbohydrates, fat, or amount of total daily calories. A novel, modified alternative method to caloric restriction is Intermittent Fasting. Purpose To determine the acute effect of four weeks of Intermittent Fasting on body composition, stress levels, sleep quality, and quality of life. Methods Sixteen participants, 9 males and 7 females, with mean age 34.0 ± 11.7 years, completed a four‐week session of Intermittent Fasting. Participants were excluded if they had Diabetes or Metabolic Syndrome. The participants fasted for 16 hours from the time of their last meal of the evening to the start of their first meal the following day. Once the fast was broken, the participants were required to consume their normal daily caloric intake within an 8‐hour period, with no requirements on the number of meals. Participants did not make changes to their activity levels throughout the four weeks. Body composition was determined using the InBody 770 (InBody USA, Cerritos, CA). The Pittsburgh Sleep Quality Index and the Cohen Perceived Stress Scale were administered to determine sleep quality and self‐awareness of stress levels. Quality of Life was assessed using the 36‐Item Short Form Survey Instrument. Results Following four weeks of Intermittent Fasting, there were significant reductions in mean body fat percentage (26.2±2.5 vs. 25.4±2.5, p=0.01), visceral fat (cm 2 ) (98.2±15.3 vs. 94.1±15.6, p=0.003), body fat mass (lbs) (47.5±6.6 vs. 46.2±6.9, p= 0.02), trunk fat (lbs) (25.2±3.5 vs. 24.2±3.5, p=0.001) and stress levels (14.1±1.9 vs. 11.0±1.4, p=0.03). There were no significant acute changes in sleep quality and overall quality of life. Conclusion Intermittent Fasting can be an effective option to help lower body fat and more importantly visceral fat. This in turn, could potentially aid in decreasing obesity‐related diseases. Our pilot study demonstrated potential health related benefits from an acute Intermittent Fasting program that could be incorporated into whole person wellness programs. Further research is needed to expand these positive findings over different time segments.