The majority of studies were observational in nature and showed a reduction in energy intake following surgery , as well as inadequate intakes of micronutrients and protein , and an excessive intake of fats .
There was evidence of nutrient imbalances , suboptimal compliance with multivitamin and mineral supplementation , and limited follow-up of patients .
The current evidence base suggests that despite being effective in reducing energy intake , bariatric surgery can result in unbalanced diets , inadequate micronutrient and protein intakes , and excessive intakes of fats .
In combination with suboptimal adherence to multivitamin and mineral supplementation , this may contribute to nutritional deficiencies and weight regain .
Bariatric surgery is currently the most effective treatment for morbid obesity .
These procedures change the gastrointestinal system with the aim of reducing dietary intake .
Improving diet quality is essential in maintaining nutritional health and achieving long-term benefits from the surgery .
The aim of this systematic review was to examine the relationship between bariatric surgery and diet quality at least 1 year after surgery .
Gastric bypass surgery for obesity decreases the reward value of a sweet-fat stimulus as assessed in a progressive ratio task.
BACKGROUND Obesity is among the leading causes of disease and death . Bariatric surgery is the most effective treatment of obesity . There is increasing evidence that after gastric bypass surgery , patients and animal models show a decreased preference for sweet and fatty foods . The underlying mechanism may include alterations in taste function . OBJECTIVE We hypothesize that a gastric bypass reduces the reward value of sweet and fat tastes . DESIGN In this prospect i ve case-control study , 11 obese patients who were scheduled to undergo a gastric bypass and 11 normal-weight control subjects in the fed state  clicked a computer mouse to receive a sweet and fatty c and y on a progressive ratio schedule 10 wk apart ( in patients , testing took place 2 wk before and 8 wk after gastric bypass surgery ) . Subjects worked progressively harder to obtain a food reward ( reinforcer ) until they stopped clicking ( ie , the breakpoint ) , which was a measure of the reinforcer value . Breakpoints were assessed by the number of mouse clicks in the last completed ratio . The experiment was repeated in a different cohort by using vegetable pieces as the reinforcer . RESULTS Breakpoints in the test sessions of control subjects correlated highly for both reinforcers . The median breakpoint for c and ies , but not vegetables , was reduced by 50 % in the obese group after gastric bypass . Patients with the largest reduction in the breakpoint had the largest decrease in BMI . CONCLUSIONS Gastric bypass surgery result ed in the selective reduction of the reward value of a sweet and fat tastant . This application of the progressive ratio task provided an objective and reliable evaluation of taste-driven motivated behavior for food stimuli after obesity surgery
The majority of studies were observational in nature and showed a reduction in energy intake following surgery , as well as inadequate intakes of micronutrients and protein , and an excessive intake of fats .
There was evidence of nutrient imbalances , suboptimal compliance with multivitamin and mineral supplementation , and limited follow-up of patients .
The current evidence base suggests that despite being effective in reducing energy intake , bariatric surgery can result in unbalanced diets , inadequate micronutrient and protein intakes , and excessive intakes of fats .
In combination with suboptimal adherence to multivitamin and mineral supplementation , this may contribute to nutritional deficiencies and weight regain .
Bariatric surgery is currently the most effective treatment for morbid obesity .
These procedures change the gastrointestinal system with the aim of reducing dietary intake .
Improving diet quality is essential in maintaining nutritional health and achieving long-term benefits from the surgery .
The aim of this systematic review was to examine the relationship between bariatric surgery and diet quality at least 1 year after surgery .