Gastric sleeve portion sizes: how much can you eat?

What a sleeve actually leaves behind

A gastric sleeve removes roughly 80% of the stomach and leaves a narrow tube holding about 100 to 150 millilitres, against 1,000 to 1,500 millilitres before surgery. That is the whole mechanism: the food that fits at one sitting drops to a few tablespoons, and the region of the stomach that produces most of the hunger hormone ghrelin leaves with the resected portion. Nothing is rerouted, and no device is left inside you.

Month one: millilitres, not plates

For the first two weeks you drink, water, thin soup, diluted yoghurt, sipped slowly across the day rather than swallowed in one go. Weeks three and four bring pureed food at roughly 60 to 90 millilitres per meal, six small meals a day. Most patients find this phase easier than they feared, because appetite is genuinely absent rather than suppressed by willpower. The difficulty in month one is remembering to drink enough, not resisting food.

Where portions settle by month twelve

By three months a meal is around 150 millilitres, a small bowl. By a year most patients sit at 200 to 250 millilitres and can manage a normal plate of protein and vegetables if they take their time over it. The sleeve widens slightly and permanently as it heals, which is expected rather than a failure. What must not happen is grazing between meals, which refills the tube repeatedly and quietly cancels the restriction.

The rule that matters more than volume

Protein first, then vegetables, then anything else, and no drinking for thirty minutes either side of a meal, because liquid washes food straight through the tube and lets you eat far more than you should. We build this into a twelve-month dietitian programme that runs from your pre-operative assessment through your first year, by video call once you are home. Patients who keep those calls hold their result; those who disappear at month four usually do not.

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