You write down your meals for a set time, often 3–14 days. Include details like portion size, cooking methods, and when you eat. This creates a clear picture of carbs, protein, fats, fiber, and key micronutrients.
Next, you review the entries for patterns. For example, you may notice low fiber, frequent high-sugar snacks, or meals that are too close together. Tracking also helps you see how hydration and meal timing affect hunger and energy.
From a microbiome view, foods influence which gut microbes grow. Fiber and fermented foods can increase beneficial fermentation, helping produce short-chain fatty acids that support gut lining and metabolism. A diary can guide you to adjust foods that match your digestion and tolerance.