Avoiding Nutrient Gaps While on a GLP-1

We've talked a lot about how we eat less overall on a GLP-1. Now let's focus on what that means for your nutrient intake — and how to make sure those smaller amounts of food still cover your body's needs.

Why nutrient gaps happen

Your body needs the same amount of vitamins and minerals day to day regardless of how much food you are eating. The problems start when food intake drops significantly, and it can become much easier to fall short especially if meals are lacking variety or rely on a narrow range of familiar foods.

This side effect of GLP-1 medications can be easily overlooked because being deficient in nutrients doesn’t show up as quickly as nausea or fatigue does. It builds quietly, over weeks and months.

Key nutrients to keep an eye on

Vitamin B12 Important for energy and nerve function. Found in eggs, dairy, fish, poultry, and fortified foods.

Iron Supports energy levels and oxygen delivery in the body. Found in lean meats, beans, lentils, and leafy greens (pair with vitamin C-rich foods like citrus to help absorption).

Calcium Important for bone health, especially during a period of weight loss. Found in dairy, fortified plant milks, tofu, and leafy greens.

Vitamin D Works alongside calcium for bone health. Our best source is sunlight - spend time outside every day. Foods like oily fish, egg yolks, and fortified foods contain some vitamin D

Fibre It's easy to not eat enough fibre when food volume drops. It plays a big role in digestion.

A food-first approach

The goal isn't to eat more — it's to make what you are eating count. Some simple swaps that help:

· Including a protein source with every meal, since many protein-rich foods also carry B12, iron, or calcium

· Adding colour and variety where you can, rather than relying on the same few "safe" foods every day – think about ‘eating the rainbow’- this will help cover vitamins.

· Choosing processed foods that are fortified. For example cereals, plant milks

· Choose fibre rich foods – wholemeal/grain breads and cereals, fruit and vegetables every day

When to consider testing or supplementation

Food-first is the goal, but it isn't always enough — especially if your food intake has dropped a lot, or you've been on a GLP-1 for several months. Having blood tests before you start and then along the way (it depends how long you are using the medication for) checking things like B12 and iron can help catch gaps early, and a dietitian or your doctor can help you decide if a supplement makes sense for your situation.

The takeaway

Eating less doesn't have to mean missing out on key nutrients — but it does take a bit more intention. Small, consistent choices around variety and nutrient-dense foods go a long way.

Not sure if you're covering your bases? We can review your eating pattern and flag any gaps worth addressing.