The medication handles your appetite. The challenge most people run into is not willpower but side effects, and the two most common by far are nausea and constipation. The good news: both respond well to simple changes in what and how you eat. Here is a practical, food-first guide.
Why GLP-1 medications cause these side effects
GLP-1 medications work partly by slowing how quickly your stomach empties. That is helpful for appetite, since food stays with you longer and you feel full sooner. But the same slowdown has two side effects: food sitting longer can trigger nausea, and moving through the gut more slowly can cause constipation. Both are most common when you first start or increase a dose, and both usually settle as your body adjusts. What you eat makes a real difference in the meantime.
Foods that help with nausea
When nausea hits, the goal is gentle, bland, low-fat food that is easy to digest. Rich, greasy, fried or very sugary foods tend to sit heavily and make it worse.
Easier choices include plain crackers, toast, rice, oats, bananas, plain Greek yogurt or skyr, clear broths and soups, and skinless chicken or white fish. Cold foods with less smell are sometimes easier than hot, aromatic meals.
Just as important is how you eat: small amounts spread through the day rather than large meals, eating slowly, and staying upright for a while afterwards. Sipping water, ginger tea or peppermint tea between (not during) meals can settle the stomach too.
Why it matters: nausea is the number one reason people struggle in the first weeks on a GLP-1. Managing it with food, rather than pushing through, makes it far easier to stay consistent and keep your nutrition on track.
Foods that help with constipation
Constipation is the other common complaint, and the fix is a familiar pair: fibre and fluid, together.
Lean on high-fibre foods: vegetables, fruit (especially with the skin on), beans, lentils, chickpeas, wholegrains, oats and chia seeds. A tablespoon of chia or ground flaxseed stirred into yogurt or oats is an easy daily boost. The key rule is to increase fibre gradually, because a sudden jump can cause bloating and gas, which is the opposite of what you want.
Fibre only works with enough water, so raise your fluids as you raise your fibre. GLP-1 medications can blunt thirst, so aim for around 8 to 10 glasses of water or other sugar-free drinks a day, ideally on a schedule. Our water intake calculator can help you set a target. Gentle daily movement, even a short walk, also keeps digestion moving.
Getting enough protein when you feel unwell
Side effects can make it tempting to live on crackers and toast, but protein still matters, especially for preserving muscle while you lose weight. On queasy days, gentle protein sources are your friend: Greek yogurt, skyr, cottage cheese, eggs, protein smoothies and soups with beans or chicken. A cold protein smoothie is often tolerable when solid food is not. For more on hitting your protein target with a small appetite, see our guide to GLP-1 friendly foods.
What to limit
A few things reliably make both side effects worse: greasy, fried and fast foods, very rich or creamy dishes, large portions, fizzy drinks, and too much caffeine or alcohol (both can worsen dehydration). You do not have to avoid these forever, but easing off during the first weeks or after a dose increase usually helps a lot.
The bottom line
The two most common GLP-1 side effects, nausea and constipation, are usually manageable with food and fluid. Eat small, bland, low-fat meals for nausea; build up fibre and water for constipation; keep protein gentle but present. Both tend to ease with time. For the wider eating approach, see GLP-1 friendly foods, and once side effects settle, our guide to eating well after GLP-1 covers keeping the results.
This article is for general information only and is not medical advice. GLP-1 medications and their side effects should be managed under medical supervision. Contact your doctor or pharmacist if side effects are severe, persistent, or stop you eating or drinking normally.