Food Hypersensitivity-Induced Chronic Gastrointestinal Inflammation in a Non-Human Primate Model of Diet-Induced Obesity

In the 2019 study involving 40 Southern pigtail macaques (20 males and 20 females), a high-fat diet (HFD) led to unexpected chronic weight loss, alopecia, malabsorption, protein-losing enteropathy, and severe gastrointestinal inflammation, particularly in female macaques. The HFD included lard, grains, dairy, and fructose and was administered for three months, followed by a return to a standard diet for another three months. The adverse effects were sex-specific and fully reversible upon reverting to a standard diet. Female macaques experienced an average of 15% weight loss during the HFD phase, with some losing more than 20%, and showed significant weight and body fat increase after returning to a regular diet. Male macaques did not exhibit the expected weight gain on the HFD, with some losing weight and others gaining minimally, but they showed significant weight gain and an increase in body fat after switching back to a standard diet. The study concluded that a HFD can induce significant health issues in female macaques, with recovery upon diet normalization, and that male macaques respond differently to the HFD. The findings emphasize the need for careful diet selection in non-human primate models of obesity to avoid severe chronic gastrointestinal inflammation and other health complications.