Timing of food intake is associated with weight loss evolution in severe obese patients after bariatric surgery

Clin Nutr. 2016 Dec;35(6):1308-1314. doi: 10.1016/j.clnu.2016.02.007. Epub 2016 Feb 16.


Background: Recent research has demonstrated a relationship between the timing of food intake and weight loss in humans. However, whether the meal timing can be associated with weight loss in patients treated with bariatric surgery is unknown.

Objective: To evaluate the role of food-timing in the evolution of weight loss in a sample of 270 patients that underwent bariatric surgery with a follow-up of 6 years.

Methods: Participants (79% women; age [mean ± SD]: 52 ± 11 years; BMI: 46.5 ± 6.0 kg/m2) were classified according their weight loss response patterns after bariatric surgery: good weight-loss-responders (67.8%), primarily poor weight-loss-responders (10.8%) or secondarily poor weight-loss-responders (21.4%). Then, they were grouped in early-eaters and late-eaters, according to the timing of the main meal (before or after 15:00 h). Obesity and biochemical parameters, energy and macronutrients intake, energy expenditure, sleep duration, and chronotype were studied.

Results: The percentage of late eaters (after 15:00 h) was significantly higher in the primarily poor weight-loss-responders (∼70%) than in both secondarily poor weight-loss-responders (∼42%) and good weight-loss-responders (∼37%) (p = 0.011). Consistently, primarily poor weight-loss-responders had lunch later as compared to good and secondarily poor weight-loss-responders (p = 0.034). Age, gender and type of surgery were not determining. Surprisingly, obesity-related variables, biochemical parameters, pre-surgical total energy expenditure, sleep duration, chronotype, calorie intake and macronutrients distribution, were similar among groups.

Conclusions: Weight loss effectiveness after bariatric surgery is related to the timing of the main meal. Our preliminary results suggest that the timing of food intake is important for weight regulation and that eating at the right time may be a relevant factor to consider in weight loss therapy even after bariatric surgery.

Keywords: Circadian; Severe obesity; Timing of food intake; Weight loss.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Bariatric Surgery*
  • Body Mass Index
  • Eating*
  • Energy Intake
  • Energy Metabolism
  • Female
  • Humans
  • Male
  • Meals
  • Middle Aged
  • Obesity, Morbid / surgery*
  • Sleep
  • Time Factors
  • Treatment Outcome
  • Weight Loss*