Lauren P. Durkee, John C. Sieverdes, Wesley D. Dudgeon. College of Charleston, Charleston, SC.

BACKGROUND: Intermittent fasting (IF) is a dietary method to restrict caloric intake during a limited time of day. Clinical trials have found mixed results in changes of body composition and improved cognitive affective states such as concentration and mental acuity. Evidence to date has predominantly focused on middle-aged adults with pre-existing conditions. Therefore, the primary purpose of this feasibility study was to explore the effects of short-term (4-weeks) IF on mental acuity in young women, with secondary interest changes in body composition. METHODS: Twenty-two female subjects were randomized to either IF (n = 11) or a control groups (n = 11). The IF group was instructed to only consume calories in an 8-hour window each day for 4 weeks without intentionally changing the type/amounts of food they consumed. Baseline, mid-point and follow-up physical measures included Dual-X-ray absorptiometry (DEXA) to assess body composition while acuity testing included Cogstate computer-based testing with additional measures of alertness (i.e., Zogim-A and fatigue (FSS)). RESULTS: No statistically significant differences between groups were found for Cogstate testing measurements including psychomotor function, information processing speed, visual attention, visual learning, working memory and attention or for FSS or Zogim-A scales. IF group analysis showed improvements in visual learning (i.e. One Card Learning test) at 2 weeks (delta = .077 [SD.11], p = .05) and at 4 weeks (delta = .078 [SD .06], p = .002) with effect sizes of .674 and 1.30, respectively. Additionally, both groups increased their paired associate learning scores at 2 weeks (IF: p = .02, Cohen’s d = .832; control: p = .10 Cohen’s d = .884) and 4 weeks (IF: p = .001, Cohen’s d = 1.346, control: p = .023, Cohen’s d = .808). There were no observed changes in weight status, body fat, or lean mass over the course of the 4-week intervention. CONCLUSIONS: This pilot feasibility study found small changes in the visual learning domain of acuity during the 4-week trial IF trial. Implications of the trial suggest that other cognitive or acuity measures may be more sensitive to IF as the present study reported minimal findings. Future studies could focus on longer intervention durations, other cognitive measures or investigate diet restriction in conjunction with IF.

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