Sugar Cravings 1

Understanding the Science of Sugar Cravings

January 15, 2020

Are you considering weight loss surgery but are wondering how your eating habits will change after? Are you afraid of losing some of your favorite foods? If you’re a sweet eater like I am, it is a topic worth exploring. Many patients express the concern to me that after surgery, they won’t be able to eat a specific favorite food. I try to reassure them that it’s more important to focus on making nutritious choices the majority of the time, but also to expect changes in food desires after surgery, including sugar cravings.

It may not be so much a matter of what you can’t have, but about what you do and don’t crave anymore.

The Basics of Sugar Cravings

Let’s talk basics of sugar and cravings. Sugar is just one simple type of carbohydrate, but it has complex effects on the body and the brain. It is digested relatively quickly, beginning about 15 minutes after eating it, and may leave you hungry again soon.

The brain uses a good amount of carbohydrates and sugars for energy, and humans show a predisposition to sweet tastes from infancy. This is likely due to deeply ingrained biological mechanisms as sugary items are calorie-dense and promote survival and growth. This trains us to find calorie-dense foods more palatable.

This works great in times of famine or starvation, but our food access has changed dramatically in the last 100 years or so. Generally speaking, Americans have highly processed, sugary foods and beverages available at their fingertips for very low costs, whereas these were luxury items in years past. This has contributed in part to the obesity epidemic in recent years.

A craving is defined by Merriam-Webster as “an intense, urgent, or abnormal desire or longing.” Cravings tend to be specific to a certain food item or type and may not be satisfied by substitutions.

Women tend to exhibit more cravings than men do. Negative emotions have been shown to increase food consumption in general, particularly “comfort” foods, which may vary from person to person. Stress eating has been linked to the brain giving off a pleasure response.

Studies done in rats have even gone so far as to identify areas of the brain being signaled in response to sugar just as it would to drugs such as opioids.

Essentially, the rats became dependent on a constant influx of sugar, leading to more cravings. The jury is still out on whether or not this correlates to humans, as well as if food addiction is real. If you find that you struggle with intense cravings or addiction before surgery, it is worth exploring this with your mental health care professional, as well as your entire health team to find.

Do Sugar Cravings Change After Surgery?

Now that we understand a little more of the basics, how do these cravings change after surgery? For one thing, many patients experience the taste and smell changes after surgery. Foods tend to have a more pronounced taste and smell. Common sensitivities after surgery include sweet and high-fat items. Sweets taste too sweet, and high-fat items may taste “greasy.” There’s also a decreased pleasure response to these flavors. Effectively, you aren’t getting quite that same “high” as you may have before surgery.

Some other things to consider are potential adverse effects from sugary items after surgery. These occur mostly in the types of surgeries that change absorption, such as the Roux-en-Y gastric bypass or Duodenal Switch. The most common ones include dumping syndrome and reactive hypoglycemia.

Dumping Syndrome

Dumping syndrome is caused by food emptying too rapidly from the stomach into the intestines. Highly refined sugars tend to be the major culprits of this. Symptoms include sweating, nausea, abdominal cramping, and diarrhea. This may last a few minutes or a couple of hours, and while not necessarily damaging, it is very unpleasant.


Hypoglycemia is low blood sugar. This can happen in patients with or without diabetes. Reactive hypoglycemia happens after ingesting something very sugary on its own. Again, symptoms can occur within a few minutes or a few hours of consuming the item, and symptoms include shakiness, confusion, cold sweat, weakness, and changes in vision and/or speech. It is possible that having adverse effects after eating sweets may help curb cravings due to negative reinforcement. We begin to associate those foods with unfavorable consequences.

Studies have shown that as individuals follow low carbohydrate or low-fat diets report cravings for those particular food items diminish over time, and even were still decreased two years later. This study included behavioral treatment as well. This could be applied to post-surgery lifestyle changes, as well as these are food groups that are mostly restricted post-operatively.

Food Cravings Before and After Weight Loss Surgery

One particularly interesting study measured individuals’ food cravings before and after weight loss surgery. They did this by using a Food Craving Inventory. This gave participants a list of 28 food items and they indicated how often they craved this item within 30 days. Foods were classified into four categories: sweets, starches/carbs, fast food, and high-fat foods. Participants also indicated how often they actually ATE these items. This was done before surgery as well as at three months and six months after surgery.

The results were interesting. It showed that sugar cravings dropped after surgery AND patients reported less consumption of the craved items. This indicates to me that not only are there changes with surgery that affect tastes and cravings but possibly also affect the response to cravings.

It may be simply an increased awareness after having gone through the surgical process and intense education on nutrition and prioritizing what foods to eat first, but it could also be an as yet unknown signaling change induced by surgery.

Overall, I recommend being mindful of your cravings before surgery, but also keep in mind that surgery is not only changing your stomach. The journey potentially changes your mindset, your tastes, smells, and desires.

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Emily L. Thevis, RDN, CSOWM, CDE is an Bariatric Coordinator for Memorial Hermann Memorial City Medical Center in Houston, TX. She is also the Metabolic and Bariatric Surgery Clinical Reviewer for Northwest Weight and Wellness in Everett, WA. Emily earned her BS in Nutritional Sciences from Louisiana State University. She is a Certified Specialist in Obesity & Weight Management and Certified Diabetes Educator. She is the 2019 Excellence in Emerging Practice Award winner for the Weight Management Dietetic Practice Group, and a member of the American Society for Metabolic and Bariatric Surgery, Obesity Action Coalition, and the Academy of Nutrition and Dietetics.

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