Vegetarian or vegan on a GLP-1: how to get enough protein

The 30-second summary

• Vegetarian and vegan eating works on a GLP-1, but protein needs a plan. Your appetite is smaller, and plant foods bring fibre and bulk along with their protein.
• In our own recipes, vegetarian dishes run shortest on protein. The vegan recipes have a median of 27 g a serving, the vegetarian ones 23 g, because eggs and cheese in small amounts do not add up as fast as tofu does.
• Watch B12, iron, calcium, vitamin D and iodine, especially if you are vegan and eating much less than before.

Why protein takes more planning

A 2025 joint advisory from the American College of Lifestyle Medicine, the American Society for Nutrition, the Obesity Medicine Association and The Obesity Society notes that enough protein can be hard to get on a GLP-1, because appetite is lower and tastes can change. It suggests eating protein-rich foods first in a meal, and it lists beans, peas, lentils, wholegrains, dairy and eggs among the protein sources to encourage.

Two things make it harder, though.

Plant protein comes with bulk. A bowl of lentils brings fibre and water along with its protein, and the advisory notes that foods high in protein, fat or fibre slow the stomach further. That is good for staying full, and a problem when you can only manage a few bites.

Plant protein does a little less per gram. A review in the Journal of Nutrition found that soy and wheat protein produce a smaller muscle-building response than several animal proteins, which it put down to lower digestibility and, in most plant proteins, less of the amino acid leucine. Two of its suggestions are practical for anyone: eat more plant protein, and combine different sources.

What the trials show

The encouraging part is what happens when people do eat enough.

• Vegans and omnivores, 12 weeks. In a trial published in Sports Medicine in 2021, 19 young men who were habitual vegans and 19 omnivores did the same resistance training twice a week. Protein was brought up to about 1.6 g per kg of body weight a day in both groups, with soy protein for the vegans and whey for the omnivores. Muscle and strength gains were not different between the groups.
• A high-protein vegan diet, 10 weeks. In a trial published in the Journal of Nutrition in 2023, young adults training five days a week ate about 2 g of protein per kg a day from either an omnivorous or a vegan diet rich in mycoprotein. Lean mass, muscle size and strength increased by similar amounts.

Be clear about the limits. These were young, healthy people doing structured resistance training, and nobody was taking a GLP-1 medicine. What they show is that, in those conditions, the source of protein made little difference once people ate enough of it.

What our recipe data shows

We checked this against the foodose recipe collection, where every figure is calculated from USDA records and published in our downloadable nutrition data.

• The 50 vegan recipes have a median of 27 g of protein a serving.
• The 121 recipes that are vegetarian but not vegan have a median of 23 g, and 28 of them come in under 20 g.
• Recipes that are not vegetarian, almost all of them with meat or fish, have a median of 37 g.

Part of the gap is that most vegan recipes are dinners, while many vegetarian ones are breakfasts. But comparing dinners only, the difference holds: 28 g for vegan against 24 g for vegetarian.

The reason is where the protein comes from. The vegan recipes get most of theirs from firm tofu and tempeh. The vegetarian recipes lean on eggs, cottage cheese and small amounts of cheese, which, in the amounts these recipes use, add up to less protein than the tofu in the vegan dishes. The lesson for a vegetarian cook is simple: add tofu, cottage cheese, Greek yoghurt or lentils to dishes that stop at an egg and some cheese.

Protein that fits a small appetite

Figures are per 100 g, from each ingredient's USDA FoodData Central record.

If you eat eggs and dairy:

• Greek yoghurt (plain, 2% fat): about 10 g. Needs no cooking.
• Cottage cheese: about 11 g. Eat it from the pot, or stir it into eggs or pasta.
• Eggs: about 13 g.
• Firm tofu: about 17 g. Works in vegetarian cooking too, not only vegan.

If you are vegan:

• Tempeh: about 20 g.
• Firm tofu: about 17 g.
• Cooked lentils: about 9 g, with fibre alongside.
• Chickpeas (tinned, drained): about 7.1 g.
• Unsweetened soya drink: about 3.6 g. Choose one fortified with calcium and B12.

On a small appetite, put the tofu, tempeh, eggs or yoghurt on the plate first and eat them first. Let the beans, grains and vegetables fill in after.

The nutrients to watch

Eating less food means less room for everything else, and the joint advisory warns that the big drop in intake on these medicines can leave people short of vitamins and minerals. Vegetarians and vegans have a few specific ones to watch. (See nutrient gaps on a GLP-1.)

• Vitamin B12. The NHS says it is found in meat, fish, milk, cheese and eggs, so vegetarians who eat dairy and eggs can usually get enough. For vegans, sources are limited and a supplement may be needed. Fortified breakfast cereals, fortified unsweetened soya drinks and fortified yeast extract all help.
• Iron. The NHS says iron from plant foods is absorbed less well than iron from meat. Eating foods with vitamin C at the same meal helps, and so does not drinking tea or coffee during or straight after main meals. Pulses, wholemeal bread, fortified cereals, dark leafy greens, nuts and dried fruit are good sources.
• Calcium, vitamin D, iodine and selenium. The NHS lists these alongside B12 as nutrients that are harder to get on a vegan diet, and suggests fortified foods or supplements.

The joint advisory also says supplements can be considered for at-risk nutrients such as vitamin D, calcium and B12, tailored to each person. Ask your prescriber or pharmacist before starting one.

A day of eating, two ways

These are illustrations, not prescriptions. Each dish is a full recipe with its portion stated and its nutrition calculated.

Vegetarian:

• Breakfast: Spinach and cottage cheese baked eggs
• Lunch: Egg and cottage cheese sandwich
• Dinner: Tomato, mozzarella and lentil bake

Vegan:

• Breakfast: Chickpea flour omelette with mushrooms
• Lunch: Warm tofu and potato mustard salad
• Dinner: Mushroom and tofu stroganoff

One honest gap: the collection is short of vegan breakfasts, and the one above is lighter on protein than the rest of the day. A glass of fortified soya drink alongside it helps. For more, browse the vegetarian GLP-1 recipes and the vegan GLP-1 recipes.

What to do with this

How much protein you need depends on your weight and your dose, not on whether you eat meat. The calculator works out your own protein floor, along with your calorie target and how much you are likely to manage, and the protein floor it gives does not change with what you choose to eat.

Get your numbers

Sources

1. Mozaffarian D, et al. Nutritional priorities to support GLP-1 therapy for obesity: a joint advisory from the American College of Lifestyle Medicine, the American Society for Nutrition, the Obesity Medicine Association, and The Obesity Society. Obesity Pillars 2025. PubMed
2. van Vliet S, et al. The Skeletal Muscle Anabolic Response to Plant- versus Animal-Based Protein Consumption. J Nutr 2015. PubMed
3. Hevia-Larraín V, et al. High-Protein Plant-Based Diet Versus a Protein-Matched Omnivorous Diet to Support Resistance Training Adaptations: A Comparison Between Habitual Vegans and Omnivores. Sports Med 2021. PubMed
4. Monteyne AJ, et al. Vegan and Omnivorous High Protein Diets Support Comparable Daily Myofibrillar Protein Synthesis Rates and Skeletal Muscle Hypertrophy in Young Adults. J Nutr 2023. PubMed
5. NHS. The vegan diet. nhs.uk
6. NHS. Vitamin B. nhs.uk
7. US Department of Agriculture, Agricultural Research Service. FoodData Central. fdc.nal.usda.gov

Medical disclaimer: Articles in the foodose research library are educational, not medical advice. Talk to your prescriber or a dietitian about your own nutrition. See our full medical disclaimer.