Vitamin D deficiency is already common worldwide before GLP-1 enters the picture. Once people stop eating enough fatty fish, fortified dairy, and egg yolks — which happens gradually as fullness increases — the gap widens. Fatty fish, fortified dairy, and egg yolks are among the main dietary vitamin D sources.

Iron deficiency is the most common micronutrient deficiency worldwide. Low iron can contribute to fatigue, weakness, dizziness, and feeling cold. Red meat, seafood, beans, 🫘 lentils, and spinach are among the richer dietary sources — foods people gradually eat less of as portions shrink.

B12 supports nerve function and red blood cell production. It's found primarily in animal products — meat, seafood, 🥚 eggs, and dairy. When overall food intake drops substantially, B12 intake drops with it.

Low magnesium has been linked to muscle cramps, weakness, and fatigue. Beans, 🫘 lentils, pumpkin seeds, spinach, and whole grains are among the richer sources — all foods that tend to disappear from meals as portion sizes shrink.

The target is 1.2 grams per kilogram of body weight per day. That number doesn't move just because appetite did. Most people on GLP-1 are not hitting it.

Sodium, potassium, and magnesium help regulate hydration, nerve signaling, and muscle function. Nausea, vomiting, diarrhea, and reduced food intake all lower electrolyte intake. The symptoms — dizziness, headaches, cramps, weakness — often arrive before anyone connects them to what stopped getting eaten.

The fix is usually the same

Small balanced meals eaten consistently. 🥚 Eggs, Greek yogurt, 🐟 salmon, sardines, beans, 🫘 lentils, leafy greens, fortified foods. The nutrients most commonly affected on GLP-1 are the ones that disappear when people stop eating varied whole meals.

Foodbe

June 4, 2026

👖 What vitamins are most deficient on GLP-1?

Note: This article is for informational purposes only and does not constitute medical advice.

The medication didn't create the deficiency. The not-eating did.

GLP-1 receptor agonists suppress appetite significantly — and the nutrients that go missing are almost always the ones that disappear when overall food volume drops. The medication works. The nutrition gap follows quietly.

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