Caffeine and Bariatric Surgery 2

Caffeine and Bariatric Surgery: A Good Match?

October 10, 2018

Caffeine and bariatric surgery is a hot topic right now. Searching online provides an enormous amount of conflicting information and can be very confusing. Does caffeine dehydrate you, or harm your stomach? Does it promote weight loss, or increase appetite? Is it good or bad? Can you never drink caffeine again, or continue to drink a pot of coffee each day?

Caffeine has long been thought to help promote weight loss, even outside of surgery. Many retail weight loss supplements use this as an active ingredient. Does it really work? Caffeine has been shown to increase thermogenesis, which is a way your body burns calories by producing heat. It has also been linked to a decrease in the amount of food you eat. So in this way caffeine can help limit your calorie intake and increase your calorie output, which is the perfect combination for weight loss. The thought then follows, “shouldn’t I drink a lot of caffeine after surgery to maximize my weight loss?”

Caffeine and Bariatric Surgery Recovery

Your surgical team may advise you to limit your caffeine intake after surgery. Why is this? One main reason caffeine intake is restricted post-operatively is due to caffeine being an irritant. Coffee, in particular, is acidic and can irritate the stomach lining as you are healing. This could simply lead to unpleasant stomach upset and reflux symptoms, or potentially the development of ulcers. Yikes! If you are noticing stomach discomfort or any signs of heartburn, eliminating caffeine may be a step worth taking to alleviate this.

Some research is showing that caffeine may also effect wound healing. Although caffeine does have some antioxidant properties, it actually has been shown to inhibit production of part of the outer layer of skin, called the keratinocytes. This indicates that consumption of caffeine could potentially inhibit incision site healing and delay your recovery.

Caffeine and Dehydration

Does caffeine dehydrate you? For many years we have thought of caffeine as a diuretic that can cause you to lose water by increasing your urine output. More recent studies are showing that a moderate amount of caffeine consumption does not actually lead to dehydration, though.

But what is considerate a “moderate” amount? Moderate caffeine consumption is generally considered to be 250-400 mg per day. More than this could actually produce diuretic effects, though it is difficult to exceed this initially after surgery.

Consider the amount of space you have in your stomach pouch? Can you drink more than 3-4 cups of coffee or 8 glasses of tea PLUS reach your daily protein goal, and get all of your vitamins and minerals in? Try tracking your average daily caffeine consumption by using the estimates below:

Estimated Caffeine Content of Popular Drinks

  • Coffee, brewed at home: 95 mg
  • Coffee brewed at a coffee shop: 200-475 mg
  • Espresso: 50 mg
  • Soda (regular or diet/zero): 34-46 mg
  • Black tea: 25-50 mg
  • Green tea: 25-30 mg
  • Energy drinks: 150 mg
  • Certain diet pills: 200 mg

Logging your daily caffeine intake can be helpful to gauge where you are at on a typical day. If you are exceeding 400 mg per day, evaluate if you are experiencing any diuretic or dehydration effects.

Dehydration is the most common cause of readmission after bariatric surgery. It’s much more difficult to get in the same amount of hydrating fluids in with such a small stomach capacity. Reaching 48-64 ounces per day can be a full time job initially. It is important to recognize the signs and symptoms of dehydration. These could include dark urine or a decrease in urine frequency, dry mouth and skin, fatigue, nausea, weakness, dizziness, and headache.

If you are drinking caffeinated beverages to the exclusion of all other fluids, it may be beneficial to explore alternatives.

Caffeine and Absorption of Nutrients

Maintaining your nutritional status when eating such small amounts after surgery can be difficult. It is imperative to take your vitamin and mineral supplements post-operatively to stay healthy long-term as you are more at risk for deficiencies.

Caffeine has been suspected to inhibit the absorption of some nutrients, though. Iron, in particular, seems to be at risk. It is not necessarily due to the caffeine content of coffee and tea, but rather is attributed to other contents in these caffeinated beverages, called polyphenols. These can inhibit iron absorption. Make sure to consume coffee and tea away from iron rich foods (don’t eat and drink at the same time, either!). Take your iron supplementation separately from your caffeinated fluids as well.

Caffeine and Sleep

Caffeine is known to disrupt sleep patterns. Insufficient or poor quality sleep can lead to metabolic changes and an increase in hunger hormones. This means you may have more of an appetite. Lack of sleep and subsequent feelings of fatigue can also make it more difficult to be physically active to be able to burn off any excess calories.

Studies have shown that consuming caffeine even up to 6 hours prior to bedtime can decrease your sleep time and quality. If this only happens to you occasionally it may not cause long-term issues, but if occurring regularly over time your body may respond with weight gain.

Daytime fatigue can also lead to increased caffeine consumption the next day to make up for lack of rest, which can create a vicious cycle that is difficult to get out of. Try to restrict your caffeine intake to earlier in the day, and have a set cut off time for your afternoon pick me up.

Caffeine and Bowels

Caffeine has been shown to have a correlation with the motility of the colon, which could prompt bowel movements or loose stool. Bowel habit changes can be common after bariatric surgery. Loose stools may occur when you are restricted to a liquid diet, so caffeine may worsen this. However, constipation can occur frequently on a high protein diet so caffeine may be beneficial in this respect.

Caffeine and Bariatric Surgery Conclusion

So what is the verdict? The truth is that much more research is needed in the area of caffeine and its effects in the bariatric population. Most studies have been conducted on athletes or other individuals who have not undergone any sort of gastrointestinal surgeries. It is also known that each individual may react differently to caffeine. If you are a habitual consumer you may feel fewer effects than someone who rarely indulges.

People who are unaccustomed to caffeine consumption may feel the effects more acutely-you may notice you are more jittery, sleep more poorly, or have increased urination more so than a person who drinks coffee all day every day.

In summary, limit your caffeine intake for about the first month after surgery to help the healing process. It is okay to include minimal amounts, but not to the exclusion of your other fluids. It may be helpful in maintaining weight loss in combination with your diet and activity long-term.

Consult with your surgical team for individual recommendations. Your team’s guidelines may differ from the information in this article. Always feel free to discuss your questions and concerns with your medical staff.


Emily L. Thevis, RDN, CSOWM is an outpatient dietitian for Northwest Weight and Wellness experienced in bariatrics and diabetes education. Emily earned her BS in Nutritional Sciences from Louisiana State University, her dietetic internship at North Oaks Regional Medical Center. She is a Certified Specialist in Obesity & Weight Management. Emily previously was the Bariatric Coordinator at Our Lady of the Lake in Baton Rouge, LA. Emily is a member of the American Society for Metabolic and Bariatric Surgery, Obesity Action Coalition, and Academy of Nutrition and Dietetics.