The effects of bariatric surgery on psychological aspects of eating behaviour and food intake in humans.

Bariatric surgery has emerged as an increasingly popular weight loss intervention, with larger and more endurable weight loss compared to pharmacological and behavioural interventions. The degree of weight loss patients experience varies, between individuals, surgeries and over time. An explanation as to why differing weight loss trajectories exist post-surgery could be due to the complex interplay of individual differences in relation to eating behaviours and appetite. Thus the aim of this narrative review is to explore literature between 2008 and 2018, to assess the impact of impact of bariatric surgery on food selection and nutrient status, on eating behaviour traits and on disturbed and disordered eating behaviour, to determine their impact of weight loss success and weight loss trajectories. Immediately post-surgery, up until 1-2 years post-surgery, there is a reliance upon the surgery's alteration of the gastrointestinal tract to control food intake and subsequently lose weight. Energy intake is reduced, dietary adherence is higher, supplement intake is higher, appetite ratings are lower, there is a reduction in psychopathology, and an increase in wellbeing. After this point, patients become more susceptible to weight regain, as this is the point where passive observation of the weight reducing action of surgery, moves into more cognitive effort, on the part of the individual, to control energy intake. There are various factors which influence an individual's ability to successfully regulate their energy intake post-surgery, such as their level of Disinhibition, Restraint, Hunger, Emotional Eating, Uncontrolled Eating, psychopathology and wellbeing. The need for continued psychological and nutritional support post-surgery is necessary to reduce weight regain susceptibility.