Intermittent fasting as an alternative weight loss approach

Abstract

_Background_: Rates of overweight and obesity continue to increase. Obesity is considered a complex, multifactorial disease that is associated with several comorbidities. Losing weight and treating obesity continues to prove difficult in that weight loss is difficult to maintain, possibly due to specific metabolic adaptations. Intermittent fasting (IF) – cycling between voluntary periods of fasting and non-fasting over a given period - has been popularized recently and may be a uniquely effective weight loss approach in that such metabolic adaptations are circumvented. This study aimed to compare IF to the standard daily energy restriction (DER) on several aspects, including weight loss, to help determine if IF is a viable weight loss approach.¶ _Methods_: Participants (n =219) were recruited through Amazon Mechanical Turk. Participants were men and women ages 18 – 65 years old, English-speaking, lived within the United States, and had a BMI of 25 – 45 kg/m2, without medical comorbidities or an eating disorder. Participants participated in a weight loss regimen of either daily energy restriction (DER) or one of two types of IF, alternate day fasting (ADF) or time-restricted feeding (TRF). Participants completed demographic measures. Participants were asked to fill out questionnaires including an adherence question, the Satiety Labeled Intensity Magnitude, Profile of Mood States, Quality of Life Scale, and the Three Factor Eating Questionnaire -Revised 18 regarding their experiences with the diet to which they subscribe. ¶ _Results_: There were 89 participants in the ADF group, 65 participants in the TRF group, and 65 participants in the DER group. The mean age of the participants was 36 years (SD = 9.4) and most participants identified as men (54%) and white (90.8%). The three groups did not statistically significantly differ in terms of percent weight lost, H(2) = 1.41, p = .492. There was a difference in adherence rates such that the TRF diet group was 1.38 times more likely than the DER group to follow the diet as prescribed and 2.36 times more likely than the ADF group to follow the diet as prescribed. The three groups did not significantly differ in terms of hunger rates, H(2) = 0.40, p = .819, but the ADF group reported higher levels of satiety compared to the DER group (r = .21, p = .027). There was no significant difference between the three diet groups regarding total mood disturbance, H(2) = 3.18, p = .204. The DER group reported a better quality of life than the TRF group (r = .25, p = .015). Finally, the three groups did not differ in terms of cognitive restraint, H(2) = 0.90, p = .638 or uncontrolled eating, H(2) = 5.96, p = .051. However, the TRF group reported lower levels of emotional eating compared to the ADF group, (r = .28, p = .003). ¶ _Conclusion_: The two IF protocols – TRF and ADF – were comparable to DER in terms of weight loss, rates of hunger, total mood disturbance, cognitive restraint, and uncontrolled eating. TRF appeared to confer some advantages relative to ADF and DER in that participants reported greater adherence to TRF and lower levels of emotional eating. However, these results should be interpreted with a degree of caution given the relatively small sample size and limited research on IF. Additional research is warranted to elucidate the differences between various IF protocols and the standard DER