Weight Loss Surgery, Carbohydrates and Exercise

Why do I feel nauseous during and after my exercise sessions? Why do I get sluggish three miles into a run? Why do I start getting weak about half-way through my strength training workout? Why are my workouts great at the beginning of the week, but by the end of the week it is all I can do to get motivated enough to get to the gym? These are some of the most common problems I see people facing upon initiating an exercise program after weight loss surgery. While there could be a number of different reasons to explain each one of these issues after weight loss surgery, the majority of time these questions can all be answered with one simple word. Carbohydrate.

For good reasons, such as wound healing and maintenance of muscle tissue to name a couple, protein becomes the priority macronutrient after weight loss surgery. Unfortunately, protein does very little to fuel exercise and is only part of the equation when it comes to exercise recovery. With protein being the focus in addition to significant caloric restriction after weight loss surgery, this combination places limits on an individual?s ability to exercise intensely and/or for long durations. Even though protein is not the primary source of energy during exercise, the most common answers I hear to the questions presented above always include protein and more protein. Rarely is carbohydrate ever given a mention.

Fueling Exercise

Glycogen, the body?s storage form of carbohydrate, is the primary source of fuel during most forms of exercise. Glycogen is stored in muscle and in the liver. Exercise and periods of caloric restriction can deplete glycogen stores quite rapidly. As glycogen is depleted, fatigue often results and muscles depend more on blood glucose (blood sugar) to fuel exercise. Ingesting carbohydrates prior to exercise and perhaps during exercise, if the exercise bout is long enough, will assist in stabilizing blood sugar levels and wards off fatigue. 

Those who have not had weight loss surgery and consume a normal diet, but can generally head out for a run or go to the gym for an hour and not experience too many issues with nausea, dizziness or fatigue. Why? Because a normal diet at approximately 2,000 calories per day generally includes a significant amount of carbohydrate. Therefore, glycogen stores are sufficient and will support an hour of moderately intense activity without ?refueling.? This is one of the reasons you often hear that if your exercise sessions are not more than 60-90 minutes long, there is no need to consume carbohydrate during exercise. This may be true for those who consume a normal diet but keep in mind that the caloric restriction imposed by weight loss surgery has a tremendous impact on glycogen stores. If you are consuming 500-1,200 calories a day and participating in regular exercise, your glycogen stores are and will remain low. It is most likely not going to require more than 60-90 minutes of exercise to deplete glycogen levels when calorically restricted. It may only require 15-30 minutes to deplete glycogen, perhaps less, before you start depending more on blood glucose. In this case, if you have not eaten any form of carbohydrate prior to exercise or you are not consuming carbohydrate during exercise, you may be unable to maintain appropriate blood glucose levels which often results in nausea, dizziness and fatigue.  

This does not mean that you should put aside protein and focus entirely on carbohydrates throughout the day. For the purposes of pre-exercise nutrition however, due to the restrictive nature of weight loss surgery, your pre-exercise nutrition should focus on carbohydrates. Since the amount of food you can consume at one sitting is restricted, you want the majority of your pre-exercise food to contain fuel for the exercise you will perform. This concept applies to nearly everyone, regardless of whether they have had weight loss surgery or not. So, instead of chugging down that protein shake before you hit the gym, 60-120 minutes prior to exercise, try foods like oatmeal, bananas, apples, or whole grain bread. These are high quality carbohydrates that will maintain blood glucose levels and should not upset your stomach. Prior to exercise, avoid foods such as legumes which are very high in fiber and may cause gastrointestinal distress. Additionally, if you still find yourself struggling to get through an hour of exercise, do not hesitate to try a sports drink or carbohydrate gel pack. Keep in mind that for those who do experience dumping syndrome, most sport drinks and gels do contain some carbohydrate with a high glycemic index, so start slow and find one that suits your needs.


While there are a number of things that could be discussed in regard to exercise recovery, protein synthesis and glycogen replenishment are two issues that will briefly be discussed here (are you getting tired of hearing about glycogen yet?).

Similar to the answers of ?protein and more protein? I often hear as solutions to the questions asked in the beginning of this article, you see the same suggestions in magazine ads, TV ads or just about anything related to ?health and fitness.? Someone or some supplement company is always suggesting that you consume this massive protein shake to recover after exercise. While protein is important for recovery, it seems that most people are confused about the quantity of protein necessary to stimulate protein synthesis (muscle growth and repair). As usual, carbohydrate often seems to be left out of the post workout recovery equation. So what do you really need?

In order to clearly illustrate what is important after an exercise session, let?s first look at what is suggested for someone consuming a normal diet without weight loss surgery. For optimal recovery from an exercise session that is fairly intense or of long duration, the suggested carbohydrate to protein ratio is 4:1 or 5:1. That?s right! Four to five times more carbohydrate is needed than protein for optimal recovery. To elaborate further, the quantity of carbohydrate should be from 50-75 grams. That means that for someone consuming a normal diet, their post workout recovery nutrition should consist of at least 50 grams of carbohydrate and approximately 15 grams of protein.

I am in no way, shape or form suggesting that someone who has had weight loss surgery try to consume this quantity of carbohydrate and protein after exercise. I am simply using this example to demonstrate that in order to stimulate protein synthesis and replenish glycogen, more carbohydrate than protein is needed. Again, due to the restrictive nature of weight loss surgery, smaller quantities of carbohydrate and protein must be consumed. Post exercise sources of carbohydrate can be similar to those consumed prior to or during exercise while simply adding a small glass of milk, part of a protein bar, or a small protein shake will help meet your protein needs after exercise.

Summing it up

Whether it be by the media, friends, message boards or medical professionals, to some extent many people have been conditioned to think that protein is the end all, be all nutrient to fuel and recover from exercise. This simply is not the case regardless of whether you are strength training, endurance training or both.

The suggestions above in no way offer a perfect solution. The amount of caloric restriction associated with weight loss surgery, most notably during the first 12 months after surgery, make it impossible to completely replenish glycogen and maximally stimulate protein synthesis. The goal after weight loss surgery however, is not to become a world class athlete, so a perfect solution is not necessary.

Exercise is an extremely important component and often a predictor of long-term weight loss maintenance. For the sake of long-term adherence to an exercise program, it helps to actually enjoy the exercise you are participating in. Imagine that! You should be able to exercise intensely for an hour without getting overly fatigued or nauseous and simple adjustments to your diet will allow you to do this. Carbohydrate is an important fuel for exercise and sufficient quantities of carbohydrate will prevent some of the issues discussed here and will help you reach your fitness goals.

High Carbohydrate Foods

A list of high carbohydrate foods includes whole grain cereals, whole wheat bread or bagels, oatmeal, whole grain pastas, whole grain muffins, bananas, grapes, apples, oranges and strawberries.

Jeremy Gentles, MA, CSCS is ObesityHelp?s staff Exercise Physiologist.

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