Life on a GLP-1: eating, exercise and injections

What should I eat on a GLP-1?

Smaller meals with protein first. You will eat less, so each bite needs to count for protein, fibre and fluids.

A 2025 advisory from four US nutrition and obesity groups proposes 1.2–1.6 g of protein per kg of body weight a day during weight loss.¹ The everyday minimum for adults is 0.8 g per kg.¹

For a 90 kg (198 lb) person, that works out to 108–144 g a day.¹ But using your full body weight can overestimate what you need.¹ So the same advisory offers a simpler goal: 80–120 g a day.¹ It also warns against staying at 2 g per kg or more for long.¹ If you have kidney disease, ask your doctor before eating more protein.

Eating the protein part of your plate first helps you finish it before you feel full.¹ The advisory favours beans and lentils, dairy, fish, eggs and chicken. It suggests keeping red and processed meat low.¹

Protein in everyday foods in Canada

We worked out each serving from Health Canada's Canadian Nutrient File.² Each line says whether the food is weighed raw, cooked or from a can.

Source: Health Canada, Canadian Nutrient File, protein per 100 g, multiplied up to each serving and rounded to whole grams.²

A worked example: 100 g chicken breast, 150 g Greek-style yogourt and 200 g baked beans add up to about 47 g of protein.² That is more than half of the 80 g goal.

Smaller meals, fibre and fluids

• Small meals. Vomiting is more likely after a large meal.¹
• If you feel sick: try a small breakfast, then small meals every 3–4 hours.¹
• Fibre, slowly. Go easy on high-fibre food in the first few days. After that, add fibre gradually to prevent constipation.¹
• Fluids. Losing fluids through vomiting or diarrhea can harm your kidneys.^1,9 The advisory says to drink enough fluids.¹ For alcohol, see Questions people ask.

How do I keep my muscle?

Do strength exercise at least 3 times a week, and eat enough protein. Walking alone protects less muscle than walking plus strength training.¹

Not all the weight you lose is fat. In one semaglutide trial, of every 10 kg (about 22 lb) lost, about 4 kg was "lean mass": muscle and other non-fat tissue. About 2 kg of that was muscle.¹

The 2025 advisory suggests strength training at least 3 times a week, plus at least 150 minutes of moderate activity, like brisk walking.¹ The plan should match your fitness level.¹

What about holidays, Ramadan and other fasts?

Big meals make vomiting more likely, so take small plates and stop early.¹ Fasting needs a plan, especially if you take insulin or a sulfonylurea (a type of diabetes tablet, such as gliclazide).^10,14

Thanksgiving, Christmas and other big meals

Thanksgiving dinner, Christmas, office parties, weddings, Diwali, Lunar New Year and Eid meals all follow the same rules:¹

• Small portions, eaten slowly, with the protein first.¹
• Fewer rich, fried and sweet dishes.¹
• Keep alcohol to a minimum.¹
• You don't have to finish what you're served, or have a second helping to be polite.

If your injection day lands on a big day and you'd rather move it, you can, as long as there are at least 3 days between two doses.^3,6

Ramadan

The main international guidance is the 2021 Ramadan guidelines from the International Diabetes Federation and the Diabetes and Ramadan International Alliance (IDF-DAR).^13,14

• GLP‑1 medicines can be used while fasting, if taken on schedule with a doctor's oversight.^13,14 Don't stop without medical advice.¹³
• Finish dose increases first. The guidelines say that once the dose has been stepped up at least 2 to 4 weeks before Ramadan, no further changes are needed.¹⁴
• Weekly injections stay on the same day each week.^3,6
• Watch for dehydration and constipation. Use the eating window for fluids, fibre and protein.¹
• The research is mostly on older GLP‑1 medicines (liraglutide, lixisenatide and exenatide). The 2021 guidelines don't name semaglutide or tirzepatide, and say more research is needed.¹⁴

Other fasts

We found no Canadian guidance written for GLP‑1 users during other religious fasts, such as Yom Kippur, Lent, Navratri or Karva Chauth. Plan any fast with your doctor, especially if you're still stepping up your dose.

How do I inject, and what if I miss a dose?

Inject once a week, on the same day, into your belly, thigh or upper arm. Use a new needle and a new spot each time.

• Where: just under the skin of the belly, thigh or upper arm.^3,6 For Zepbound, the back of the upper arm is for someone else to inject.⁶
• When: any time of day, with or without food.^3,6
• Rotate: use a different spot each week.⁶
• Needles: a new needle every time. Don't store the pen with a needle on.¹⁰
• Never share a pen, even with a new needle. It can spread serious infection.¹⁰

Getting rid of needles and pens

• Use a sharps container. The labels say to put used pens and needles in a closable, puncture-resistant sharps container, or follow local rules.^3,6
• Free containers and take-back. The Health Products Stewardship Association runs free take-back of used sharps and unwanted medicines through participating pharmacies in several provinces, and gives out free sharps containers.²⁰ Ask your pharmacy; arrangements vary by province and town.
• Never put needles or pens in household garbage or recycling, and don't recycle a full sharps container.³
• Don't recap, bend or break a used needle. See where to get rid of used pens in Canada.

Missed a dose?

Never take two doses to catch up. The Canadian labels say to skip a late dose and carry on as normal on your usual day.^5,6 If you've missed more than one dose, ask your doctor before restarting. The Wegovy label says that after more than 2 missed doses, restarting on the lower dose steps may be needed.³

On tablets?

• Rybelsus (for type 2 diabetes): take it on an empty stomach, swallowed whole with no more than 120 mL (half a glass) of water. Then wait at least 30 minutes before food, drink or other tablets. If you miss a day, skip it and take the next one the following day.¹¹
• No GLP‑1 tablet is approved in Canada for weight management, as of 12 Oct 2026.⁷

How do I store it in winter, and travel with it?

Keep unopened pens in the fridge. Once in use, most can sit outside the fridge for a few weeks, but only below 30 °C. In Canada, the bigger risk is often freezing.

Store new pens at 2–8 °C, away from the cooling element. Never freeze them, and never use one that has frozen.^3,5,6 Keep the cap on to protect the pen from light.³

From the Canadian product monographs. Generic semaglutide and Mounjaro pens have their own leaflets; always follow the one in your own pack.^8,15

Travelling. At Canadian airports, needles for your own medical use are allowed in carry-on bags with the guard on, along with the medicine. Liquid prescription medicines, and the ice or gel packs that keep them cool, are exempt from the liquid limit if you declare them; keep them in their labelled pharmacy packaging.¹² Carry them with you rather than in checked bags, which can get very cold, and don't let the pen touch a frozen ice pack. Coming home from the US, residents can generally bring back medicines prescribed and filled in Canada, up to a 90-day supply.²¹ See keeping pens safe in winter and on trips.

How do I know if it's working?

Expect regular reviews of your weight, your health and side effects. The Canadian guideline looks at health gains, not just kilograms.¹⁶

1. Week 0Start on a low dose. Write down your weight and waist.
2. Every 4 weeksThe dose usually steps up, if side effects allow. If stomach side effects are bad, the next step can wait.^3,6
3. About 3 months on a full doseRegulators have traditionally used 5% weight loss at this point as the check. The guideline adds that real health gains can come whatever the amount lost.¹⁶
4. After thatRegular reviews, for as long as you take it. The guideline recommends long-term use when the medicine is working.¹⁶

For a 90 kg (198 lb) person, 5% is 4.5 kg, about 10 lb. Falling short doesn't mean you failed. Your doctor weighs up the benefits and risks of carrying on, including changes in blood sugar, blood pressure or sleep apnoea.¹⁶ Guide 3 covers the other options. And none of these medicines replaces diet and exercise: the Canadian guideline recommends them together with health behaviour changes.¹⁶

What should I keep track of?

Your weight, waist and side effects, and your sugar if you have diabetes. Bring the notes to each review.

• Weight and waist: write them down, so you can compare at your reviews. Guide 1 shows how to measure your waist.
• Blood sugar, if you have diabetes: check before you start and while you take it.⁹ Low sugar can show as dizziness, sweating, shaking, blurred vision, confusion or a fast heartbeat.⁹
• Doctor checks: your heart rate, because your resting pulse can rise on these medicines. Tell your doctor if your heart races while you are resting.⁹ Kidney tests if you've had bad vomiting or diarrhea.⁹ If you have diabetes, report any change in your eyesight: a fast improvement in blood sugar can briefly worsen diabetic eye disease (retinopathy).⁹
• Side effects and meals: note what you ate before nausea. Patterns help.
• Report side effects to Health Canada's Canada Vigilance Program, online or on 1-866-234-2345. Anyone can report.¹⁹

What about food noise and family meals?

Many people find the constant thoughts about food go quiet. Some also lose the pleasure of eating, and that can feel strange at family meals.

Studies show less "food noise", less emotional eating and fewer binges on these medicines.¹ But some people miss the joy of food, or of cooking for others.¹ If food has always been how your family shows care, that change can be hard. Talking it through, or seeing a counsellor, can help.¹

Don't skip meals for hours because you aren't hungry. Getting very hungry can bring back cravings for sweets and refined carbs.¹

At home, it helps if the people you eat with know why your plate is smaller. A simple line works: "I'm on a medicine that fills me up fast. I'll have a little of everything."

Questions people ask