grazing behavior

Effect of Grazing Behavior on Weight Regain Post-Bariatric Surgery

November 3, 2021

Bariatric surgery is considered one of the best treatments for severe obesity; however, it is not a quick fix and still involves changes to one’s diet and lifestyle. Anyone who has had bariatric surgery can attest to it; that it is not the “easy way out.” Making healthy choices and combating previous eating and grazing behavior will likely still be challenging even when 80% or more of the stomach has been removed or divided.

Impacts of Grazing Behavior on Weight Regain

One of the potentially problematic eating behaviors after bariatric surgery is grazing. Individuals that may have struggled with grazing before surgery often return to that same habit after surgery.

The authors of one study cited that as many of 80-94% of patients who engaged in grazing before surgery returned to this pattern around six months post-operation. Additionally, it is often seen that individuals that had binge eating disorder pre-operatively turned that behavior into graze eating after surgery with a prevalence potentially as high as 61%.

However, it may be difficult to truly determine the prevalence of graze eating since it varies depending on factors, including the length of time from surgery, lack of diagnostic definition, poor reporting, and/or poor screening tools. In one systematic review, the authors found the prevalence of grazing after surgery to range from 17 to 50% []. Again, individuals that had engaged in it pre-operatively were more likely to engage post-operatively as well.

What’s the Difference Between Grazing and a Snack?

But what is the difference between grazing and just having a snack? Typically grazing involves eating repetitive, unplanned meals or snacks throughout the day or over an extended period of time. The terms “picking & nibbling” or “snacking” may also be used.

Grazing is often related to feelings of a loss of control ( but isn’t necessarily part of the criteria. In fact, the authors of one study have determined there may be two subtypes of grazing: compulsive and non-compulsive.

Non-compulsive would typically be related to mindlessly snacking throughout the day or eating more frequently in an unplanned manner.

Compulsive, in contrast, would be characterized by feelings of losing control around eating.  The authors also found a greater prevalence and link to generalized anxiety disorders in those with compulsive grazing.

Since grazing results in consuming food more frequently throughout the day, this can naturally lead to an increase in total calorie intake, and thus a lack of desired weight loss and/or weight regain after surgery.

As reported in the systematic review, the authors of two different studies found that during the first 18 to 24 months post-op, many of the study participants still achieved adequate weight loss (defined as greater than 50% excess body weight loss). However, the authors of those same studies also found significant weight regain in those same individuals. (

The authors of one study reported that the prevalence of grazing increased as the time from surgery increased. At six months post-op, the prevalence was only 16%, but by two years post-op, the prevalence had increased to 45%. Those that also experienced a loss of control reported significantly more grazing than those that did not. (

Types of Foods Eaten After WLS

It might also be helpful to consider the type of food individuals are eating after surgery. “Slider foods” is a term used to describe foods that are either mushy consistency upon eating or turn into a mushy consistency quickly after chewing.

The most common foods attributed to this category include mashed potatoes and gravy, ice cream, etc., including crunchy carbohydrate “snack” foods such as crackers, pretzels, chips, etc. These foods generally lack protein and fiber, which are two important factors that promote satiety.

Highly processed snack foods may also increase grazing behavior for several reasons. One related to the fact they are mostly slider foods as previously discussed, another related to the high simple carbohydrate content, which may alter glucose levels and increase the risk for reactive hypoglycemia, and another related to the hedonic effect of, or the pleasure one receives from eating, these foods.

Reactive hypoglycemia specifically seems to occur more frequently after bariatric surgery; it results in a sharp increase in glucose after a meal, followed by an even sharper increase in insulin, resulting in a subsequent drop in blood glucose.

With that drop in blood sugar, the body and brain will naturally crave sugar or carbohydrates to return blood sugar to the normal range as quickly as possible. If corrected with a meal or snack containing only carbohydrates or simple sugars, this cycle will likely repeat itself, resulting in more frequent eating episodes to maintain blood sugar levels.


  • Work with a mental health provider if you identify as someone struggling with a loss of control around eating or feel that you are eating for other reasons than physical hunger.
  • Set a meal/snack schedule. This may be especially helpful for those who do not feel the same hunger sensation as before bariatric surgery. Ideally, eating every 3-5 hours is a good habit to adopt that avoids eating too frequently or infrequently.
  • Focus on solid foods as much as possible. In the early post-op phase, it will be necessary to focus on supplemental protein drinks and soft foods as the stomach heals. However, once you can comfortably tolerate solid foods, it is important to include more of them in your diet. Relying too heavily on soft and slider-type foods will increase the likelihood of more frequent hunger and/or grazing as soft foods and liquids may not promote as much satiety.
  • Drink plenty of non-carbonated & sugar-free fluids. Some individuals may confuse being thirsty for being hungry.
  • Reach out to your surgical team for advice and resources!
grazing behavior
Michelle Bauche


Michelle Bauche, MS, RDN, LD, CSOWM is a registered dietitian working for Missouri Bariatric Services in Columbia, Missouri. She is a certified specialist in Obesity and Weight Management and a member of the Weight Management Dietetic Practice Group through the Academy of Nutrition and Dietetics. Read more articles by Michelle!