Your Post-Gastric Bypass Diet Explained

Gastric bypass surgery can be an extremely effective way for people with obesity to lose unhealthy weight. However, it's helpful to know upfront that a post-gastric bypass diet requires significant lifestyle changes. If you're considering gastric bypass surgery, here's what you can expect afterward.

Less Room Means Small Servings

One of the main ways that gastric bypass surgery works is by shrinking your stomach to the size of a walnut. As a result, you'll find that you can only eat very small amounts of food in one sitting. However, it may take some time to learn how much your newer, tinier stomach can accommodate.

Immediately after surgery, you'll start an easy-to-digest diet of small portions of clear liquids, such as broth and juice, and Jell-O. For the first two weeks after you return home, you'll slowly advance to a diet of thicker liquids and foods, such as milk, sugar-free pudding, low-fat cottage cheese, and soup. During this time, one of the first things you'll notice is that your portion sizes will be tiny, starting with about a tablespoon or two. After the two-week honeymoon phase, you'll gradually thicken your diet with pureed foods like applesauce, mashed bananas, yogurt, hot cereal, noodles, fish, and scrambled eggs.

Small Servings Mean Greater Frequency

Over the next six weeks or so, you'll eat quarter-cup portions of these foods about eight times a day, for a total of 550-700 calories. Because protein is critical for maintaining muscle mass, you'll likely be advised to blend protein powder into your meals. At the same time, you'll want to avoid foods that are high in sugar as these can lead to dumping syndrome, a condition that rapidly pulls large amounts of water into the small intestine, potentially resulting in nausea, diarrhea, and fainting. High-fat foods, which are hard to digest, can also cause nausea.

You won't always have to eat such small meals. Once you reach the two-month mark, your eight mini meals will start to resemble normal meals a little more, combining several different foods and totaling about a half a cup in size. This will provide roughly 1,000 calories a day and enable you to get the protein you need without added protein powder. After six months, your diet will begin to take on an even more regular pattern, and you'll transition to three small meals and one to two snacks a day. Even though you'll increasingly be able to eat more solid foods, you'll want to steer clear of hard-to-digest foods, such as popcorn, nuts, dried fruit, fruit with skin, and raw vegetables.

A Focus on Fluids

Getting the two liters of fluids your body needs for proper hydration can be a challenge when your stomach doesn't hold much. Drinking between meals can help. Your goal will be to aim for one-cup servings of fluids eight times a day. Because certain fluids, like soda, can provide unwanted calories, it's important to stick with water or calorie-free beverages.

A Supplementation Strategy

In addition to limiting the amount of food you can eat, gastric bypass surgery also bypasses the small intestine, decreasing the number of calories you'll absorb. Unfortunately, this also reduces many of the nutrients your body absorbs from the food that you eat. Supplements are critical for replacing these lost nutrients. Every day, you'll take a multivitamin with minerals, as well as supplemental calcium, vitamin D, and vitamin B12. Because most vitamins are too large to pass through your smaller digestive tract, you'll want to crush these or cut them into tiny pieces.

In the first year after surgery, gastric bypass often results in dramatic weight loss. Following a carefully planned post-gastric bypass diet can help you lose that weight safely and keep your body healthy.