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Are Fad Diets Safe After Weight Loss Surgery?


By Dr. Dieter Pohl

Following elective weight loss surgery, it is common for patients to be excited to start fresh with a healthy diet. While we encourage proactive behavior in developing healthy habits we want to advise against “fad” diets because they can harm long term success. Let’s take a look below at some our dietary recommendations and how fad diets can derail them.


Avoid sugar | Culprit: Juice Cleanses

Cutting out refined sugar is one of the best changes people can make in their diet. Those who make an effort to reduce or eliminate their intake of soda, cookies, and other surgery items lose more weight and keep it off. A diet low in sugar and high in complex carbs and proteins will reduce cravings for caloric junk food. Juice and smoothie diets are often advertised as all-in-one meal plans that will help a person get all the vital nutrients they need in a convenient beverage. More often than not, these drinks don’t contain nearly enough calories and nutrients to sustain healthy weight loss. Even worse, companies often pack their products with loads of sugar or artificial sweeteners to make the drinks palatable. Even that health shake with “100% Natural Fruit Juice” is loaded with sugar. In short, be wary of “hidden sugars” in products marketed for weight loss or general health.


Limit Fat | Culprit: Keto and other low-carb diets

Although dietary fat is an essential part of a healthy diet, many Americans end up eating too much. Generally speaking, there are twice as many calories in fatty foods compared to carb and protein rich foods, which explains why some of our favorite high-fat treats--ice cream, pizza, cheeseburgers--are so caloric. Half or more of the calories in these items are fat! If lowering fat intake is such a solid way to reduce overall calorie consumption, what’s with these low-carb diets like Atkins that allow followers to not worry about fat intake, instead advising to cut out carbs? Diets like Atkins are “Keto” diets. Keto diets work by converting stored fat in the body to sugar to use as energy. Keto diets aim to deplete sugar stores in the body, thereby inducing the body to burn fat. Since any consumed carbohydrate can be readily used as sugar in the body, low-carb diets forbid followers from consuming an appropriate amount of carbs a day. With carbs off the table, users are encouraged to consume more protein and fat to make up for those lost calories that would come from carbs. This limitation can actually lead to higher fat intake, stagnating weight loss. Keto diets have been shown to be an effective weight loss tactic for some, but the method is too controversial and situational to recommend to our patients. Our post-op diets advocate for a balanced, moderate plan to sustain a healthy weight over the rest of a person’s life. Keto diets, other the other hand, are too extreme and difficult to sustain over the long term.


Increase Protein | Culprit: Vegan Diet

There are variations of vegan diets that are conducive to a healthy lifestyle. But making a transition to a vegan-based diet is not recommended for weight loss purposes. There a few reasons for this: fewer options for high-quality protein, difficulty meeting the recommended level of vitamins and minerals, and a lack of amino acids. Let’s first look at the chief concern: protein. Protein is integral to maintaining lean muscle mass, as well as keeping the body satiated throughout the day.  A diet too rich in carbs and low in protein will not provide sustained energy. This will make snacking more tempting as the body will be craving food more regularly. Additionally, animal proteins are most practical source for consuming protein, with foods like eggs and fish containing vitamins, minerals and amino acids that cannot be found in a vegan diet alone. Because the body will be recovering from an invasive surgery it is recommended to stick to a well-balanced diet and draw from healthy options of all food groups. If you are following a vegan diet for personal or religious reasons you will need to discuss appropriate diet options with your dietitian.


Eat Every 3-4 Hours | Culprit: Intermittent Fasting

There will always be people who claim success with any fad diet. Intermittent fasting is no exception, but this diet is not advised for patients post weight loss surgery. The basic tenets of intermittent fasting are to schedule a tight eating window, around 6 to 8 hours. Eating is forbidden outside of this window. We recommend weight loss surgery patients to eat small portions at regular intervals. This will limit the opportunities for mindless grazing. Additionally, some people may feel light-headed and tired if they subject their bodies to prolonged periods of calorie restriction. Some programs of intermittent fasting will allow followers to eat as much food as they want, as long as it is within the parameters of their eating window. Following a gastric bypass surgery the stomach will not be able to consume large quantities of food in a short period. Many small meals of balanced proportions throughout the day will ensure success post-op.

At the end of the day, most fad diets are really just tricks to consume fewer overall calories, thereby inducing weight loss. However, this weight loss often comes with negative consequences--whether it’s unsustainably restrictive meal plans or nutritionally deficient programs. There are no shortcuts to long-term weight loss. Remember, it’s not about the weight you lose, but what you keep off.

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