Losing weight in the months after a partial gastrectomy — surgery that removes part of the stomach — is common. The stomach normally works as a reservoir, holding food and releasing it gradually. When that space is made smaller, even a few spoonfuls can bring on a full feeling, a sensation known as early satiety. Naturally, the amount eaten at each meal drops, and when total daily calories fall short, body weight goes down.
Around three months after surgery the body is still adjusting to its new digestive anatomy. Many people lose roughly 10–15% of their pre-surgery weight during this period, and the weight usually settles somewhere between six months and a year. Because the speed and degree of loss vary from person to person, it is safest to work with your care team to judge what counts as an expected course and what is a warning sign.
Beyond simply eating less, several factors can overlap. When food moves down too quickly, some people develop dumping syndrome — dizziness, cold sweats, palpitations, cramping, or diarrhea after meals — which can make eating itself feel frightening. Changes in stomach acid and the digestive environment can also reduce absorption of iron, vitamin B12, calcium, and fat, so nutrition may fall short even relative to what is eaten. Shifting tastes, or craving only spicy food, are common during recovery as well.
At home, the basic principle is "small amounts, often" rather than "a lot at once." Instead of sticking to three meals, spreading food across five or six smaller meals and chewing slowly helps digestion and eases early fullness. Drinking water or soup about 30 minutes before or after eating, rather than during the meal, leaves more room for food. For the same volume, favor calorie- and protein-dense foods first (eggs, tofu, fish, meat, cheese), and take oral nutrition drinks as between-meal snacks rather than meal replacements.
That said, if weight keeps dropping sharply, if vomiting prevents keeping food down at all, or if severe weakness, dizziness, or fever appear, it is better to tell the hospital than to push through alone. A narrowed surgical join (anastomosis), malabsorption, or other causes may need checking, and help such as a dietitian consult or vitamin B12 supplementation may be available.
This article is general information to aid understanding and does not replace individual medical care. If weight changes or eating difficulties worry you, please discuss them with the medical or nutrition team at the hospital where the surgery was performed.