Tamil Nadu HSE Second Year Nutrition and Dietetics cheat sheet

Nutrition is the science of food nutrients, their action, interaction and balance in relation to health and disease; dietetics is its applied, therapeutic use.

Food supplies energy (carbohydrate, protein, fat), body-building material (protein, minerals, water) and protective factors (vitamins, minerals); a nutrient is a chemically defined substance needed for these roles.

Six nutrient classes: carbohydrates, proteins, lipids, vitamins, minerals and water. Carbohydrate, protein and fat are macronutrients; vitamins and minerals are micronutrients.

Energy values (Atwater): carbohydrate 4 kcal/g, protein 4 kcal/g, fat 9 kcal/g, alcohol 7 kcal/g, dietary fibre about 2 kcal/g.

Essential nutrients cannot be synthesised in adequate amounts and must come from diet: essential amino acids (9 for adults), essential fatty acids (linoleic, alpha-linolenic), vitamins and minerals.

Nutrient density = nutrient content per 100 kcal; energy density = kcal per gram of food. High-moisture foods such as vegetables are low in energy density.

Health continuum: undernutrition (deficiency) and overnutrition (excess, obesity) are both forms of malnutrition; a balanced diet prevents both.

Terms to distinguish: food (edible material), diet (habitual intake), nutrition (process), nutritional status (condition resulting from intake and utilisation).

Standard measures: 1 cup about 200 ml, 1 tablespoon 15 ml, 1 teaspoon 5 ml, 1 katori about 150 ml; raw weights are recorded before cooking.

Edible portion (EP) = as-purchased weight × edible fraction; cooking losses of water-soluble vitamins (B and C) rise with longer cooking and more water.

Cooking methods: boiling, steaming, pressure cooking, sautéing, baking, grilling and frying; pressure cooking and steaming best retain water-soluble vitamins.

Food preparation practices that reduce nutrient loss: wash before cutting, cut into large pieces, cook in minimal water, use the cooking water in gravies, avoid overcooking and adding soda.

Germination and fermentation improve nutrient availability: sprouting increases vitamin C and B vitamins and reduces phytate, improving iron and zinc absorption.

Weighed food record: weigh all raw ingredients and cooked portions, record leftovers, then calculate nutrients using food composition tables (IFCT/NIN).

24-hour recall: interviewer asks the respondent to list all foods eaten in the previous day; quick but subject to recall bias.

Food frequency questionnaire asks how often foods are eaten over a defined period; suited to ranking habitual intake in large surveys.

Consumption unit (CU): adult man sedentary = 1.0; adult woman = 0.9; child 1-3 years = 0.6; adolescent boy = 1.2; adjust household intake to per-CU values.

Practical report writing should state aim, ingredients with weights, method, nutrient calculation per portion and cost per serving.