After weight loss surgery, your stomach holds much less, so every bite needs to count. The way you eat changes for life: protein first, small portions, plenty of fluids between meals and daily vitamins. Here is how your diet progresses and the habits that help you heal and keep the weight off.

The five diet stages

Your stomach needs time to heal, so foods are added back in stages:

Stage 1, clear liquids (days 1–3): water, sugar-free popsicles, broth and sugar-free electrolyte drinks.
Stage 2, full liquids (days 4–14): low-sugar protein shakes, drinkable yogurt, skim milk and smooth soups.
Stage 3, pureed foods (weeks 3–4): blended poultry or fish, scrambled eggs, cottage cheese and mashed beans.
Stage 4, soft foods (weeks 5–6): tender poultry and fish, soft fruits and cooked vegetables.
Stage 5, regular foods (week 7 onward): lean proteins, fruits and vegetables, low-fat dairy and healthy fats.

Moving ahead too fast or skipping a stage can cause problems and slow your recovery. See every allowed food on our Pre-Op and Post-Op Diet page.

The everyday rules

Protein first: aim for at least 60 grams a day in the early stages. Your dietitian will set your own target as you progress.
Fluids: at least 48 ounces a day for women and 64 ounces for men, sipped slowly.
Drink between meals, not with them: drinking while eating fills your small stomach and can push food through too fast. Your dietitian will tell you how long to wait.
Small bites: chew each bite well and take your time with every meal.
Stop when you feel full: eating past the first sign of fullness can cause pain or vomiting.
No straws or big gulps early on: they bring air into your stomach.
Limit sugar and greasy foods: they add empty calories and can cause dumping syndrome.

Foods that are often hard at first

Some foods can be hard to tolerate in the first months: dry or tough meats, bread, rice and pasta, and raw, stringy vegetables. Add foods back one at a time, in small amounts, so you can tell what agrees with you. Our diet plan adds whole grains in moderation after 6 months.

What is dumping syndrome?

Dumping syndrome happens when sugary or fatty food moves into the small intestine too quickly. It can cause nausea, cramping, sweating, a racing heart, dizziness or diarrhea, usually soon after eating. It is more common after gastric bypass. Limiting sweets and fried foods and eating slowly usually prevents it.

Alcohol

We advise patients to avoid alcohol after surgery. It interferes with healing, adds calories with no nutrition, and is absorbed faster after weight loss surgery, so it affects you more quickly and more strongly than before. Research also shows a higher risk of alcohol problems after some bariatric operations, especially gastric bypass.

Vitamins for life

Because you eat less, and after bypass absorb less, you will need vitamin and mineral supplements every day for life. Most patients take a bariatric multivitamin, calcium and vitamin B12, and some also need iron. Learn more on our bariatric vitamins page.

Working with our dietitian

You will not have to figure this out alone. Our bariatric dietitian works with you before and after surgery, in English or Spanish, and builds a plan around your needs and the foods you like.

Sources

Mechanick JI, et al. Clinical Practice Guidelines for the Perioperative Nutrition, Metabolic, and Nonsurgical Support of Patients Undergoing Bariatric Procedures, 2019 Update (AACE/TOS/ASMBS/OMA/ASA). Surg Obes Relat Dis. 2020;16(2):175-247.
King WC, et al. Alcohol and other substance use after bariatric surgery: prospective evidence from a U.S. multicenter cohort study. Surg Obes Relat Dis. 2017;13(8):1392-1402.
Houston Surgical Weight Loss Pre-Op and Post-Op Diet, After Surgery, Discharge Instructions and Bariatric Vitamins pages.

This article is general information, not medical advice. Talk with your doctor about what is right for you.

Diet After Bariatric Surgery: What You Need to Know