Eating Well on GLP-1 Medications: How to Avoid Nutrient Deficiencies

GLP-1 receptor agonists (such as semaglutide and liraglutide) are medications that mimic one of our body’s natural gut hormones. Glucagon-like peptide-1 (GLP-1) is a hormone that is naturally produced in the small intestine after we have eaten. Its functions include supporting insulin secretion, which helps manage blood glucose levels, and regulating gastric emptying.  This means  they help to regulate blood sugar, reduce appetite and slow digestion — which is why they can be so effective for improving metabolic health or supporting weight loss. However, they can also lead to reduced food intake and nutrient deficiencies if nutrition isn’t carefully managed. In my experience – and this is based on what I’m told by clients who take these medications - this is often not discussed when they are prescribed. However, nutritional shortfalls can have some serious consequences, especially for women in midlife, as pointed out below.

Why nutritional shortfalls happen

GLP-1 medications slow how fast food leaves your stomach and increase feelings of fullness. That can mean smaller meals, skipped meals, or avoiding heavier foods. Over time, this can reduce both calorie and nutrient intake — particularly protein, iron, calcium, vitamin D, and B vitamins — all crucial for maintaining energy, muscle mass and bone health.

Prioritise protein

Protein is essential for maintaining muscle mass, supporting metabolism and keeping you full between meals. Aim for at least 1.6 g of protein per kg of body weight per day, or roughly 30 g per meal. However, needs are highly individual and it’s best to work with a qualified nutritionist to ensure you get what you need.

Good options include eggs, Greek yoghurt, cottage cheese, chicken, fish, lean red meat, tofu, tempeh, lentils and protein smoothies.

Support bones and muscles

Rapid or prolonged weight loss can lead to loss of lean mass (which includes muscle) and bone density — especially in midlife women. Many of my clients are perimenopausal women, and I have talked in other blog posts about the fact that this group is losing a great amount of muscle anyway and how this impacts their metabolic health. Having muscles is not just about how good you look in a bikini. Instead it’s about metabolic health. Muscle tissue is the largest site of glucose uptake, so when we have less muscle, the body’s ability to regulate blood sugar decreases. The result is weight gain, particularly around the tummy. You might think ‘this is not a problem because I have the GLP-1s that regulate my blood sugar’, but what happens when you come off them and have less muscle? Your metabolism is worse than before and you are more likely to put the weight back on, especially as your appetite won’t be suppressed anymore and you actually feel like eating!

Having less muscle tissue also puts us at the risk of increased falls. Fractures, especially when they occur in osteoporotic women, can have a devastating effect on peoples’ lives.

What to do to avoid this?

Lift weights 2–3 times per week  - invest in some sessions with a PT to ensure you do this correctly.  Ensure adequate calcium, magnesium and vitamin D from dairy, fortified plant milks, sardines, leafy greens, and sunlight, plus the afore mentioned protein.

Eat fibre

Ensure that you eat plenty of fruits, vegetables, whole grains, nuts, seeds and legumes to support blood sugar levels, regular bowel movements and support gut microbiome health. Aim for 25-30g of dietary fibre day. If your appetite is significantly reduced, focus on quality and consistency rather than volume – make every snack or meal count!

Make sure that hydration is kept up! Sudden high fibre intake can lead to constipation, which can already be a problem for some GLP-1 users. Drink at least 2l a day of water and/or herbal teas to keep things moving.

Don’t forget your micronutrients

Because food volume drops, micronutrient gaps can appear. Focus on iron, B12, folate, calcium, vitamin D, magnesium, potassium, zinc and antioxidants. Eat a variety of colourful vegetables, fruits, lean proteins and whole foods.

Eat less, but eat better

When appetite is lower, food quality matters more. Focus on nutrient-dense meals, smaller portions, and balanced plates with protein, vegetables, healthy fats and slow-burning carbohydrates. Stay hydrated and maintain fibre intake to support digestion.

Special considerations for women in midlife

During perimenopause and menopause, hormonal changes make muscle and bone preservation critical. Combine GLP-1 therapy with protein-rich meals, resistance training, and nutrients like calcium, magnesium, vitamin D and K2. If still menstruating, continue to monitor iron, B12 and folate levels.

Key takeaway

GLP-1 medications can be powerful tools for metabolic health — but they work best when paired with a nutrient-dense diet, movement and regular health monitoring. Think of it as ‘eating less, but eating smarter’ — every bite should nourish muscle, bone, hormones and energy.

There are lots of other things to consider too, especially strategies to get off the medications once you have achieved your desired weight loss. If you want to see how a nutritionist can help you pair GLP-1s with a nutrient dense diet, book here for a 1:1 consultation. We can work together on a road map to achieve long lasting weight loss, strong muscles and bone health.