Current guidelines recommend continuous energy restriction for weight loss along with long-term lifestyle behavioural change as the cornerstones of weight management. Time restricted eating versus continuous energy (calorie) restriction is one of the great debates when it comes to weight management. The most common form of weight loss strategy is continuous dietary (calorie or energy) restriction. Time restricted feeding, which includes intermittent fasting, has specified time limited windows of feeding and fasting. These periods within the 24hour cycle need not be energy restrictive, and people may follow the regime intermittently. When interpreting current evidence there are several factors to be considered including timing and length of the eating window, if there is predefined or spontaneous energy restriction, and whether the change in eating behaviour causes a change dietary composition as well as body weight. Evidence in humans is currently limited to short-term studies of 12-16weeks, with a variety of eating windows of 4-10hours. Where energy intake is maintained (isocaloric) but the dietary pattern is changed, there is some weight loss (2%) and it is notable that greater weight loss is achieved with a reduced number of meals. With ad libitum intakes there is evidence of some weight loss (2-4%). Metabolic changes related to glucose control, lipids and blood pressure, have some potential but results are not equivocal, and it is unclear if the outcomes are independent of weight loss. Benefits and challenges to applying time restricted eating in clinical practice are summarised below. Overall, findings suggest that this approach may suit some people, and offer an alternative to continuous energy restriction, but results are not superior.
|Tool to use as an option for a person-centred approach||Will not suit everyone due to lifestyle, environment, cultural and personal preferences|
|May be easier to frame with ad libitum intake during eating period||Eating behaviour may impact outcomes e.g. breaking fast with high energy foods|
|Simple regime to follow||Eating window should be adhered to every day|
|No recommendations for intake composition||Eating habits within the window may not be ideal for nutritional adequacy|
|Restricted time eating window has some variation (up to 10hrs)||Even drinks containing energy (kcals) have to excluded during fasting periods|
|May support weight lost maintenance after a more restrictive regime||Weight loss over long-term unknown|
30 Jun 2021 - 01 Jul 2021