Can stomach stretch after gastric sleeve? If so, what does it take to stretch?

Yes, the stomach can stretch after a gastric sleeve, but it usually doesn’t return to its original size. The stomach is designed to expand and contract, and while the sleeve removes about 80% of the stomach, the remaining portion is still elastic.
Stretching occurs gradually over time, mainly due to consistently overeating. Regularly eating beyond fullness, especially high-calorie, soft, or liquid foods like ice cream, can lead to increased stomach capacity. Carbonated drinks may also contribute by putting pressure on the stomach walls. Eating large portions too often can reduce restriction, making it easier to consume more food.
To avoid stretching, it’s important to stick to portion control, eat protein first, chew food thoroughly, and avoid grazing throughout the day. Staying mindful of hunger and fullness cues will help maintain the long-term effectiveness of the sleeve. If stretching does occur, some patients find that a reset diet or revision surgery, like a re-sleeve or conversion to gastric bypass, can help.

Yes, this is possible if you go back to bad eating habits. For example carbonated drinks can stretch the stomach.

You should expect some stretching in the first 6 months to a year after surgery as the staple line relaxes a bit.  But after that, you should experience significant stretching of your pouch.  If your pouch has stretched out too much for you to be able to stay on track with your weight loss or maintenance, and you are still eating per the guidelines given to you by your surgeon (focus on protein rich foods, stay away from carbs) then you may be a candidate for a sleeve rescue surgery (fixing and reducing the size of your sleeve).  If you need help, do not be embarrassed to ask for it, there are options for you!