Recommendations for patients who have undergone gastric bypass surgery

For the surgery to be successful, it is important to maintain healthy habits throughout your life.

Main dietary rules

Give priority to protein-based meals.

• Eat small amounts slowly, chewing each bite thoroughly (to a puréed consistency).
• Sit down to eat every 3–4 hours (keep a schedule), even if you are not hungry.
• Avoid snacking. Do not get distracted while eating.
• Stop eating at the first sign of fullness.
• Avoid eating and drinking at the same time, as this can overfill the stomach and cause nausea. Drink no earlier than 30 minutes after meals.
• Do not eat bland foods. There is no need to avoid seasonings and spices.

Diet characteristics at different stages

Stage 1. Liquids

Throughout the day, drink unsweetened, non-carbonated liquids:

• plain and flavored water;
• decaffeinated coffee and tea;
• broth;
• unsweetened gelatin;
• unsweetened ice cream;
• unsweetened sports drinks.

Monitor your condition. Headache, dizziness, and dark urine indicate dehydration.

Drink in small sips. Large sips cause stomach pain.

Carbonated drinks cause bloating, burping, and discomfort.

Artificial sweeteners (stevia, aspartame, saccharin, sucralose) may be used.

Stage 2. Protein shakes

Your goal is 1.4–1.9 liters of fluids and 60–70 grams of protein from shakes daily. Hydration takes priority over protein.

If you cannot finish a shake within an hour, try again in 2 hours. You do not need to reach the goals immediately — progress gradually.

Each protein shake should contain:

• 100–200 calories;
• 15 or more grams of protein;
• less than 20 grams of sugar.

Some people develop lactose intolerance after surgery — dairy products may cause nausea, bloating, diarrhea, and cramps. If this happens, stop protein shakes for 24 hours. Later, replace milk-based shakes with whey protein isolate (lactose removed).

If you do not like the taste of shakes, add cocoa powder or powdered peanut butter (no more than 1 tablespoon per day), spices (cinnamon, ginger, nutmeg), extracts (vanilla, almond), or unsweetened syrups. If you dislike the smell, drink from a bottle with a small opening or use a straw. If you prefer chewing, freeze the shake in popsicle molds.

Stage 3A. Smooth texture

Drink 1.4–1.9 liters of fluids and take 60–70 grams of protein from shakes daily. Eat puréed foods 5–6 times a day. Begin taking vitamins and minerals.

Stage 3B. Soft texture

Continue drinking 1.4–1.9 liters daily. Take protein shakes or protein foods (minimum 60–70 g protein). Foods must be puréed or soft (easily mashed with a fork). Start with protein foods, then move to non-protein foods.

If food feels “stuck”, do not panic and do not drink water — walk a little. To keep food moist, cook in foil or add broth when reheating.

Stage 4. Regular texture

Continue drinking fluids, eating protein foods, and taking vitamins. Gradually introduce solid foods.

Daily intake:

• 8 cups (1.4–1.9 liters) of fluids;
• 8 servings (60–70 g) of protein;
• 3 servings (90–120 g) of starchy foods;
• 2 servings (200–300 g) of vegetables;
• 2 servings (300–400 g) of fruits;
• 2 servings (10 g) of fat;
• 1 serving (200–250 g) of dairy products.

For the first 3–6 months after surgery, consume hard-to-digest foods with caution:

• tough red meat, hamburger, lobster, scallops, shellfish, shrimp;
• rice, pasta, baked bread;
• fibrous fruits with thick skin (oranges, grapes, pineapples);
• fibrous vegetables (asparagus, snow peas, celery, lettuce).

Eat protein first, then vegetables or fruits. Eat starchy foods last.

Nutrition Traffic Light

Green light – eat daily

These foods should form the basis of the diet, as they provide protein, vitamins, and minerals with minimal food volume.

• High-protein foods (priority):
• lean meat (chicken, turkey, beef);
• eggs;
• low-fat and cultured cheese;
• unsweetened yogurt;
• unsweetened protein shakes.

• Vegetables (well-cooked or stewed): carrots, zucchini, potatoes.
• Fruits (puréed): bananas, baked apples.
• Porridge (well-cooked): buckwheat, oatmeal, brown rice.
• Drinks: still water (main drink), low-fat broths, weak tea, diluted unsweetened juices.

Yellow light – consume with caution, in small amounts

• High-fiber foods (hard to digest, may cause bloating, discomfort, or a “stuck” feeling):
• whole grains;
• legumes (peas, beans, lentils);
• raw fibrous vegetables (broccoli, asparagus, celery).
• Gas-producing foods: cabbage, Brussels sprouts, cauliflower.

Red light – avoid

These foods are strictly prohibited or highly undesirable, as they may cause severe discomfort, dumping syndrome, interrupt weight loss, or damage the new stomach.

Vitamins and Minerals

After gastric bypass surgery, the process of nutrient absorption changes significantly, making lifelong use of vitamin and mineral supplements essential. The best option is complete multivitamins with minerals.

For the first 3–6 months, use liquid or powdered forms; after that, you can switch to capsules and tablets. Chewable multivitamins are not recommended. They contain a high amount of sugar and are not fully absorbed by the body.

Physical Activity

To maintain a healthy weight, regular physical activity is recommended (4 hours per week or 35 minutes daily).

Exercise also helps solve other problems:

• improves cardiovascular and musculoskeletal health;
• increases strength and flexibility;
• boosts energy levels;
• promotes healthy sleep;
• improves mood.

To stay in good physical shape, it is recommended to walk more and dance. You may also engage in cycling, swimming, and water aerobics. Household activities such as cleaning or gardening are also beneficial.

Frequently Asked Questions

Will my appetite return?

Gradually, appetite and hunger may return. That is why it is important to develop lifelong healthy eating habits.

Will I be able to enjoy my favorite foods again?

Yes, over time you will be able to eat almost all foods, but in smaller portions.

How much weight will I lose?

On average, patients lose 60–80% of excess weight after surgery, but the rate may vary significantly. Weight loss usually occurs in “steps” — periods of losing weight alternate with plateaus.

How do I know how much protein I am getting?

Read food labels.

If no protein information is available, keep in mind that 7 grams of protein are contained in:

• 28 grams of chicken, turkey, or fish;
• 57 grams of firm tofu;
• 85 grams of soft tofu;
• one egg;
• half a cup of beans.

What should I do if signs of dehydration do not go away?

Drink fluids with electrolytes or salty broth, and add salt to food. If the problem persists, consult your doctor.