Learn nutrition the way the science actually supports it — and skip the fads. Master the macronutrients (carbohydrates, protein, and fat) and their calorie values (4, 4, and 9 kcal per gram), what fiber and water do, and the micronutrients that matter: the vitamins and minerals, their roles, and the classic deficiency each prevents (vitamin C and scurvy, iron and anemia, vitamin D and bone health, iodine and goiter). Practice reading a Nutrition Facts label — serving size, calories, added sugars, and % Daily Value — and the simple math of calories from macros. Every answer is grounded in consensus guidance (USDA Dietary Guidelines, NIH fact sheets) and names the common myths (a "detox" tea, "negative-calorie" foods, carbs are inherently bad). Educational only — general nutrition science, not personalized diet, medical, or clinical advice.