A registered dietitian wants you to consider these three things if you’re using GLP-1 medications to make sure you’re still meeting your nutritional needs

If you’re on GLP-1 medication, you’ve probably heard lots about how it works and what results to expect.

What you might have heard less about, is the knock-on effect GLP-1s can have on nutrition, and the impact on long-term health.

Recent research carried out by the University of Cambridge and University College London has raised concerns about the lack of nutritional advice and support for people using weight loss medication.

Registered dietitian Zoe Griffiths agrees. “Weight loss medications do not directly cause nutrient deficiencies. However, by reducing appetite, portion size and sometimes food variety, they can increase the risk of nutritional shortfalls over time if they aren’t properly supported.”

The nutrients most commonly affected include protein, fiber and micronutrients such as magnesium, iron and calcium.

Here Griffiths, who is also VP of Behavioural Medicine at digital health service Numan, tells Fit&Well about the nutritional risks those using GLP-1s need to consider—and what they can do about it.

1. Increase protein

Eating more protein is often recommended during weight loss to support muscle mass and metabolic health, helping you feel fuller for longer.

But for many people on GLP-1s, it can be tricky to meet high protein goals when appetite is low.

“My advice is to aim for a daily intake of 60–120g of protein,” explains Griffiths. “With a minimum of 60g per day though, requirements should ideally be calculated individually.”

She recommends having protein at every meal, and opting for a small-but-frequent approach to meals if needed. For example, have five smaller meals throughout the day as opposed to three large meals, if that feels unrealistic.

“Choose protein and fiber-rich foods, such as beans and pulses, to help support both muscle health and appetite regulation,” Griffiths suggests.

2. Boost fiber intake

Reduced appetite while using GLP-1s can lead to lower fiber intake, especially if you eat fewer fruits and vegetables than usual. This can lead to constipation and impact gut health.

“We all need around 30g of fiber per day, but many of us consume far less than that,” Griffiths says.

Boost your fiber intake by having a variety of fiber-rich foods at each meal, such as legumes, beans, wholegrains, vegetables, seeds and nuts.

“If you're struggling to meet your targets through food alone, fiber supplements such as psyllium can be helpful when introduced gradually and taken with adequate fluids to avoid constipation,” Griffiths explains.

3. Consider micronutrient supplements

A lack of micronutrients such as magnesium, iron and calcium can impact energy levels, immunity, bone health, cognition and overall wellbeing.

While supplements are usually only needed if there is a confirmed deficiency—and are never a replacement for a balanced diet—Griffiths suggests some might find magnesium and calcium supplements worth taking.

“For people experiencing constipation or poor sleep, magnesium might help,” she says. “Calcium intake may need to be supported if dairy or fortified alternatives are limited, but iron should only be supplemented when a deficiency has been identified with a professional.”

Working with a dietitian or registered nutritionist to identify deficiencies and create a personalized plan is best.

“Having a personalized plan which helps you find eating patterns that you can maintain long-term is the goal,” Griffiths says.