Effect of 10-hours Time Restricted Diet on Breast Cancer Risk in Pre and Postmenopausal Women with Overweight or Obesity: TRED Pilot Study

OBJECTIVES: This study examined the effect of 10-h time restricted diet on breast cancer risk, assessing changes in body weight, insulin, IGF-1, and IGF binding protein 1, 2, and 3 among pre and postmenopausal women with overweight and obesity. METHODS: Women with overweight or obesity (n = 25) were enrolled into a time-restricted diet for 6 months. Participants were instructed to eat only from 10am until 8pm and to record consumption on the TRED smartphone app. At weeks 1, 2, 12, and 24, participants were asked to complete food diaries. During the other weeks, participants simply recorded the category of food consumed (meal or snack). Compliance was calculated as percentage of days when food consumption was reported. RESULTS: 25 women with a BMI between 25 and 40 (32.3 ± 4.2) and age between 18–65 years old (46.5 ± 11.0) were enrolled. Average weight loss was 0.8 ± 4.6 kg (−0.6%). Fat percentage, muscle mass remained unchanged. Insulin and IGFBP 2 significantly increased from baseline to post intervention and to follow up. However, the change is not clinically significant. IGF-1 and IGFBP1 significantly decreased from baseline to follow up. Average adherence to the diet protocol was high: 78% of participants recorded dietary intake on at least 77% of intervention days. CONCLUSIONS: The TRED 10-hour eating window did not lead to weight loss, body fat loss, or decreasing waist circumference among pre and postmenopausal women with overweight or obesity. However, the intervention significantly improved some biomarkers of breast cancer risk (IGF-1, IGFBP 2 and IGFBP 3). FUNDING SOURCES: This study was supported by NIH/NCI training grant T32 CA193193.