As GLP-1 weight-loss medication usage surges, doubling in popularity between March 2024 and August 2025, healthcare professionals are urging those using it to rethink what’s on their plate, warning that appetite suppression can quietly lead to nutrient shortfalls if diet quality isn’t carefully managed.
What is GLP-1?
GLP-1 (glucagon-like peptide-1) is a natural hormone your body releases from the gut after you eat, and it plays a big role in blood sugar control and appetite regulation. It’s also the hormone that medications such as Mounjaro or Wegovy are designed to mimic.
Emerging evidence and clinical guidance show that reduced appetite often results in skipped meals, lower protein intake and insufficient vitamins and minerals, increasing the risk of fatigue, muscle loss and poor long-term outcomes.
We’ve teamed up with Dr Deborah Lee at Dr Fox Online Pharmacy to share a step-by-step nutrition-first framework to help people ensure their bodies are still getting what they need while managing weight with GLP-1s.
1. Start with nutrient-dense foods, not just smaller portions
Studies show that diets higher in protein and fibre are particularly important for people losing weight quickly, helping to maintain strength and metabolic health.
his looks like:
- Protein at every meal to help preserve muscle mass during rapid weight loss.
- High-fibre foods such as vegetables, pulses and wholegrains to support gut health and fullness.
- Healthy fats from foods like olive oil, nuts, seeds and oily fish to aid vitamin absorption.
2. Common nutrient gaps to watch on GLP-1s
Calorie-restricted diets have been repeatedly associated with micronutrient inadequacy when not carefully planned. There are several nutrients that may fall short during appetite-suppressed weight loss.
- Iodine - Skipping meals and calorie restriction, common with weight-loss injections, can increase the risk of iodine deficiency, already thought to affect up to half of UK adults. Iodine supports thyroid and brain health, yet intake may fall with lower consumption of dairy and fish. Prioritise iodine-rich foods or take a daily multivitamin to help meet the 140 mcg adult requirement.
- Vitamin B12 - Essential for energy production, brain health and red blood cell formation. Found in meat, fish, eggs and dairy; vegans should look to fortified plant milks, nutritional yeast or supplements. Vitamin B12 is water soluble so we need to intake daily to maintain levels. It’s best taken in the morning to support vitality throughout the day.
- Iron - Vital for oxygen transport and energy production in individuals diagnosed with iron deficiency. Best taken on an empty stomach, away from caffeine. Iron-rich foods include red meat, lentils, beans and leafy greens, especially when paired with vitamin C to improve absorption. Supplementation should only follow medical advice, as excess iron can accumulate in the body.
- Vitamin D - Helps the absorption of calcium, supporting immunity, bone strength and mood. With limited sunlight between October and March, most UK adults are advised to supplement. Best taken with a meal containing healthy fats. Natural sources include oily fish, egg yolks, liver and fortified cereals.
- Magnesium - Supports muscle function, nerve signalling, and energy production. Found in nuts, seeds, legumes, wholegrains, and leafy greens. Supplements can help if dietary intake is low and are best taken with food to aid absorption.
3. Which supplements can support GLP-1 weight management?
It’s important to emphasise that supplements should support nutritional adequacy, not promise fat loss. Evidence-led options commonly recommended alongside GLP-1 use include:
- A high-quality multivitamin to help cover daily requirements during reduced food intake.
- Vitamin D to support bone, immune and muscle health.
- Protein supplementation, where dietary intake is low, to help maintain lean mass.
Why nutrition matters more than ever
While GLP-1 medications can support weight loss, Dr Deborah Lee shares that long-term health outcomes depend on nourishment, not just weight change.
“GLP-1s change appetite, they don’t change nutritional needs. Ensuring adequate protein, fibre, vitamins and minerals is essential for energy, muscle preservation and overall wellbeing, especially when food intake is reduced.”
For more information on vitamins that suit your needs and routine, you can shop our full vitamin and supplement range. Consult your GP for GLP-1 enquiries and before taking supplements or vitamins.