The first time I really paid attention to the conversation around GLP-1s was at a food industry trade fair. Before that, I had only heard of them as a diabetes and weight loss drugs. I admit that I hadn’t thought hard about their implications for food.

Private industry picked up quickly that they need to address how they're producing food to address their concern in the face of GLP-1s: people eat less. People will eat (and buy) less of the food that the food industry produces. Buying less food presumably means spending less money.

Eating less also means that people have fewer chances to consume the right balance of nutrition. So another question was: how do food companies improve the nutritional value of their food products?

The speed at which the food industry is addressing these questions is fascinating. And my question then is: Is their concern valid? What’s coming out about GLP-1s in the science around nutrition?

An impressive amount. And we’re just starting to measure it.

GLP-1s work for weight loss and blood sugar control by decreasing appetite and slowing how fast food leaves your stomach. And eating less means you take in less of everything, including nutrients your body needs.

Many people on GLP-1s eat less than 800 calories a day. This is very little.

It’s so little that multiple nutrient deficiencies become likely, and early data supports that expectation.

Among more than 461,000 adults who had been on GLP-1s for a year, 20% had nutritional deficiencies:

Every category climbed higher, the longer people stayed on the drug.

Another study comparing GLP-1 users to people on a different diabetes drug reported that GLP-1 users were 1.5 times more likely to be low in vitamin D, and 1.5 times more likely to have low ferritin or iron-deficiency anemia.

A small diet study found nearly two-thirds of people on GLP-1s were eating less iron than they need each day. Nearly 6 in 10 weren't getting enough protein. On average, they were eating 60–75% less protein than recommended.

A small absorption study tested how much iron got into the blood after a dose. People on GLP-1s for 10 weeks absorbed about 64–80% less iron than people not on the drug.

The people on these drugs are mostly women. In the largest study, 56% of GLP-1 users were women, with an average age of 53.

That’s potentially millions of women taking medications that the data shows to be strongly associated with reduced nutrient intake and absorption.

The literature on nutrition and GLP-1s is new — mostly published in the past year. What we have is observational and as a result, we can’t prove cause and effect.

Studies point consistently in the same direction across multiple independent studies though, and the mechanism by which we understand GLP-1s to operate makes it make biological sense.

🍳 Add a protein source at your next meal. The protein shortfall isn’t unique to GLP-1 users, and many underestimate their actual intake.

☀️ Add a vitamin D source to one meal today. Vitamin D was the most common deficiency. Quick options: salmon, sardines, eggs, fortified dairy, or fortified plant milks.

🔍 Notice if you’ve been eating less lately. It could be illness, stress, dieting, or perimenopause. Many of the nutrient risks in this research apply any time intake drops.

🥗 Schedule a dietitian consult before starting (or in the early months of) a GLP-1. More than 90% of patients in the largest study had no dietitian contact before starting, and it can shape your health down the road.

📅 Set calendar reminders for nutrient labs at 6 and 12 months. Deficiency rates went up between these months.

🏋️ Add resistance training to your week. Lean mass loss has been documented, and resistance exercise is the most-studied way to limit it.