Dietitian Amanda Clark examines expectations of weight following bariatric surgery.


Typical early weight loss following bariatric surgery ranges from 47–80% of excess weight.

However, typical weight regain is 15–25% of that lost weight.

This can be very disheartening for patients and it is very important to manage expectations of weight following surgery.

With more than 22,000 people undergoing bariatric surgery per year in Australia, it is becoming increasingly common for GPs to see patients experiencing weight regain.

Weight regain after surgery may be caused by a variety of factors (Table 1).

Table 1. Contributing factors to weight regain

Problems leading to weight regain Common examples
Anatomical Enlargement of the stomach pouch, enlarged stomach outlet
Physiological Altered fat metabolism, resulting in easy fat storage and limited fat-burning; menopause
Psychological Depression; lack of self-efficacy; difficulty in asserting for new behaviours
Behavioural Inactivity; eating behaviours (eg processed foods, grazing, eating beyond satisfaction)


It is normal to see weight gain after bariatric surgery because patients still live in an obesogenic environment, and the individual’s or surgery’s ability to control all factors is limited. Body fat is also subject to metabolic pressures to regain lost weight.

There are a number of nutritional interventions for addressing common problematic eating behaviours seen to accompany weight regain (Table 2).

Table 2. Eating behaviours that may contribute to weight regain after bariatric surgery

Problematic eating behaviours Description Strategies
Chaotic eating Lacks structure; no formal eating pattern Create structure, including approximate eating times spaced throughout the day; prioritise eating within the day’s activities
Skipping meals Going long periods without food, which can result in overeating later Planning of meals, with suitable snacks or easy options for the individual’s situation
Poor food choices Highly processed, fried and fast foods; falling back on previous habits that resulted in initial weight gain Identification of easy food choices with less processing; encouraging patients to take an interest in food preparation and quality (eg cooking classes)
Grazing Small portions of food eaten over an extended period of time; previous binge eating may be expressed in this way Discrete meals of one-cup volume at meal times to ensure satisfaction
Night eating A significant proportion of calories are ingested after the evening meal Ensure adequate and even food spacing throughout the day
Excessive portion size Eating beyond ‘satisfaction’ resulting in ‘fullness’; this continues to drive excessive intakes Reduce and maintain smaller portion sizes, ideally one-cup volume at meals
Alcohol intake Alcohol is rapidly absorbed following bariatric surgery, resulting in disinhibited eating and lack of satiety from liquid calories Limit alcohol intake; alcohol problems can develop after surgery in those who previously experienced no problems and all care team members should be alert
Inadequate protein intake Protein is important for satiety but also for maintenance of muscle mass, which contributes to resting metabolic rate Education on protein content of food along with strategies, recipes and ideas for inclusion
Mixing fluids and foods This may stretch the capacity of the stomach and cause early gastric emptying Avoid fluids in the immediate pre-meal period and for 30 minutes after


Other factors that represent an opportunity for modification include psychological barriers, physical activity, sleep quality, medications and exposure to endocrine-disrupting chemicals.

It is important to assess and address modifiable contributors prior to applying a further surgery, as problems may persist.


This article was originally published on RACGP


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