Does Fasting Help You Reach Your Gastric Sleeve Goals?


Intermittent fasting (IF) is getting a lot of buzz lately, including within the VSG community. But is it really helpful when you’re trying to lose weight after gastric sleeve in Mexico? And if so, is it right for everyone? A new study provides some insight into the world of IF.

Does fasting promote weight loss?
A 10-week study done by the University of Illinois at Chicago looked at two groups of IF participants: one that fasted for 20 hours (eating only between 1 and 5 p.m.) and one that fasted for 18 hours (eating only between 1 and 7 p.m.). During fasting hours, participants were asked to stick to water or non-caloric beverages. When comparing the results to a control group that didn’t change anything about their diet, both IF groups had the exact same outcomes: a roughly 550-calorie reduction each day, a loss of 3% body weight, and lowered levels of insulin resistance.

Base on these findings, which were published in Cell Metabolism, it appears that IF does indeed provide weight loss benefits. Interestingly, fasting for longer periods—at least in the time periods studied here—doesn’t necessarily bring greater results. It’s something vertical sleeve gastrectomy patients may want to consider, especially if counting calories doesn’t appeal to you. My patient, Traci, is a fan of IF. “One year out and IF is my ‘go to’ for maintenance,” she says. “I do 16:8 (16 hours of fasting and 8 hours of eating) or 18:6 (18 hours of fasting and 6 hours of eating) and do not eat after 7:30 or 8 pm at the LATEST. Bonus is that I get tons of water in during my fasting period.”

Who shouldn’t do IF?
Intermittent fasting may help some, but it’s certainly not an across-the-board solution. If any of these situations apply to you, please skip it.

• You’re newly sleeved. While your body is healing and getting used to the different stages of a gastric sleeve diet is not the time to limit your eating periods. You’ll likely be struggling to get in all of your calories anyway. Keep in mind, too, that this is the “hot” period for VSG weight loss, when many people find the pounds falling off fairly easily.

• You’re pregnant or breastfeeding. Lots of our female patients find themselves happily pregnant after years of trying. Check with your obstetrician, of course, but pregnancy and breastfeeding periods should be about nourishing your baby—not trying new ways to lose weight.

• You’re unable to take in enough calories. VSG patients have smaller stomachs, which means most can’t eat much at any one time. If you also limit the hours in which you’re eating, you may not be able to ingest enough calories to keep your body functioning optimally. Ambra found that to be the case for her. “I was only eating 500 to 700 calories a day and I felt like all I did was eat,” she says. “The first week I dropped 5 pounds, but I couldn’t stay with it. I found it was easier for me to stay low carb.”

The decision to try IF is a personal one. Pairing it with a good gastric sleeve diet has led to success for some of my patients, but it also has a variety of potential downsides. Please speak with your primary care physician if you’re considering IF.

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