In male macaque monkeys aged 10 to 15 years, feeding a high-fat diet for 18 months is linked to a 17.86% rate of diabetes, as defined by elevated blood glucose and HbA1c levels, along with changes in...

We analyzed one study on macaque monkeys and found that a high-fat diet over 18 months was linked to a 17.86% rate of diabetes in male monkeys aged 10 to 15 years [1]. This diagnosis was based on higher blood glucose and HbA1c levels, along with changes in liver enzymes that suggest the liver was producing more glucose and breaking down less of it [1]. The evidence we’ve reviewed so far does not include any studies that contradict this finding. All available data point to a connection between the high-fat diet and these metabolic changes, which are used to define diabetes in this context. However, we did not see any information about whether these effects reversed after the diet ended, or whether female monkeys responded the same way. We also don’t know if the same outcome would happen with different types of fats, different durations, or younger or older animals. This single study suggests that, under these specific conditions, a high-fat diet may be associated with signs of diabetes in this group of monkeys. But we can’t say this happens in all monkeys, or that the diet directly causes diabetes. The link is observed, but the full picture remains incomplete. If you’re considering dietary changes for yourself or others, this finding reminds us that what works for one species or condition may not apply broadly. Monitoring how your body responds to different foods — especially over time — can be more useful than following general rules.