Dr Federica Amati: What you need to eat before starting weight loss medication?

Dr. Amati explains that GLP-1 agonists work within a complex system involving the gut, pancreas, liver, and brain, so optimizing these systems before starting medication improves outcomes. She uses a car analogy—the medication is like a performance boost, but you need to smooth the road first to avoid a bumpy ride. The gut is particularly important because it's the hormone factory that originally creates GLP-1 peptides endogenously, and most bothersome side effects are gastrointestinal in nature. If someone has existing constipation before starting GLP-1s, it will likely worsen; resolving it beforehand significantly reduces this risk. The gastric system slows down on GLP-1s, which increases transit time and can elevate gut inflammation, making it critical to support the gut ecosystem beforehand. Dr. Amati emphasizes feeding the gut microbiome with diverse fiber types (soluble, insoluble, viscous, non-viscous, fermentable, non-fermentable), bioactive plant compounds (phytochemicals), and healthy fats from sources like seeds, nuts, olive oil, and omega-3 rich fish. She recommends gradually increasing fiber from the average 12-14 grams to 30 grams daily, and aiming for 30 different plant foods weekly to maximize fiber diversity before increasing quantity. Healthy fats are often overlooked but serve as substrates for gut microbes and support enteroendocrine cell sensing pathways. She notes that fiber deficiency affects over 95% of the population, and omega-3 deficiency is also prevalent. When GLP-1 treatment begins and food intake reduces significantly, the opportunities to obtain these protective nutrients also decrease, making pre-treatment nutrition especially important. Additionally, pre-treatment nutrition serves a dual purpose—both nourishing the gut and preventing micronutrient deficiencies, which are a higher risk for GLP-1 users due to reduced food intake. She clarifies that maintaining 30 grams of daily fiber remains important even when total calorie intake is significantly reduced on GLP-1s, with supplementation potentially helping manage volume issues from slow gastric emptying.