In obese mice, injecting apolipoprotein A-IV leads to higher fat burning and a 44% reduction in food consumption within 24 hours, which causes weight loss over eight days mainly because the mice eat less, not because they burn more energy.

In obese mice, injecting apolipoprotein A-IV changes the levels of certain liver proteins involved in lipid transport, increasing those that help clear lipoproteins and decreasing those linked to artery disease, which may improve how the body processes fats.

In obese mice, a single injection of a specific human protein called apolipoprotein A-IV lowers blood sugar levels by about half within two hours by enhancing glucose uptake in fat tissues and decreasing glucose output from the liver, without involving insulin.

The mice didn’t gain or lose weight or eat differently with the drug, so the benefits aren’t just because they were eating less or changing their metabolism.

In healthy adult men, eating a diet very high in fat for a few days raises levels of a blood protein called apolipoprotein A-IV, while eating a diet very high in carbohydrates lowers it.

The drug didn’t affect blood sugar or fat levels in the blood, so its benefits aren’t due to improving how the body handles sugar or fat.