Nutrition in Human Beings: Exploring Dietary Needs and Health

ICMR's Dietary Guidelines for Indians (2024 edition) recommend the following for a sedentary adult (2000 kcal/day): Cereals 250–300g/day (prefer whole grains — millets, brown rice, whole wheat); Pulses/legumes 80–90g/day (dal, rajma, chana — primary protein for vegetarians); Vegetables 400g+/day (mix of leafy, root, and other); Fruits 100–200g/day; Milk/dairy 200–300ml/day (or equivalent); Oils/fats 25–30g/day (prefer unsaturated — groundnut, mustard, sesame); Salt <5g/day. Key ICMR warnings: (1) Indians consume 2× the recommended salt; (2) Nearly 70% of Indians don't meet the vegetable recommendation; (3) Refined cereal (white rice, maida) dominates diets — replacing even 30% with millets improves glycaemic control measurably. For physically active adults, protein needs increase to 1.2–1.4g/kg body weight. The ICMR-NIN 'Eat Right India' app provides personalised meal planning based on these guidelines.

Nutritional requirements change significantly across the lifespan: Infancy (0–2 years): Exclusive breastfeeding for 6 months (WHO/ICMR) — breast milk provides all nutrients except Vitamin D (400 IU supplement recommended from week 2); Childhood (2–12 years): Calcium peak demand for bone building (400–1,000mg/day); iron critical for cognitive development; Adolescence (12–18 years): Highest iron need ever for girls (onset of menstruation — 27mg/day vs 11mg for boys); protein for muscle growth; Iodine for brain development. Pregnancy: Folate (400–600mcg from preconception) prevents neural tube defects; iron (27mg/day); DHA for foetal brain. Older adults (60+): Protein needs increase (1.2g/kg) despite lower appetite; Vitamin D + calcium for bone loss prevention; B12 absorption declines (supplement if serum B12 <300 pg/mL). India-specific gaps: the NFHS-5 found significant stunting in children (35%) indicating chronic early-childhood undernutrition, and anaemia in 57% of women aged 15–49 — both reflecting inadequate iron, folate, and B12 across life stages.

India faces a 'triple burden' of malnutrition: undernutrition, micronutrient deficiency, and overweight/obesity simultaneously. The four most prevalent deficiencies: (1) Iron deficiency anaemia: 58% of women, 41% of children under 5 (NFHS-5). Highest risk: menstruating women, pregnant women, infants 6–24 months. Fix: iron-rich foods (rajma, palak, jaggery, sesame) + Vitamin C to enhance absorption; (2) Vitamin D deficiency: 70–90% of urban Indians (paradoxical given sun exposure — due to clothing, indoor lifestyle, pigmentation). Fix: 30 minutes sun midday 3×/week + supplementation (1,000–2,000 IU/day); (3) Vitamin B12 deficiency: 47% of north Indian adults in a 2019 study — predominantly vegetarians (B12 only in animal products). Fix: daily B12 supplement 500mcg for strict vegetarians; (4) Iodine: adequately addressed by iodised salt programme, but resurgence in areas using non-iodised salt. Annual blood tests for Vitamin D, B12, and CBC (haemoglobin) are recommended for all adults above 30.

ICMR recommendations for a sedentary adult (70kg reference): Protein: 0.8–1.0g/kg body weight = 56–70g/day. Active adults: 1.2–1.6g/kg. For vegetarians, combining different protein sources (rice + dal, roti + chana) throughout the day ensures complete amino acid intake even without meat. Carbohydrates: 50–60% of total calories. Prioritise complex carbs (millets, oats, whole grains) with GI <55; limit simple sugars to <10% of total calories (<50g/day for a 2,000 kcal diet). Fats: 20–30% of total calories. Saturated fat (ghee, butter, coconut oil) <10% of calories; unsaturated fats (groundnut, sesame, mustard oil) preferred. Trans fats (vanaspati, partially hydrogenated oils) <1% of calories — FSSAI has mandated near-zero trans fat content in packaged foods since 2022. Practical Indian context: the typical North Indian diet is often 65–70% carbohydrate (primarily refined), 10–12% protein, 18–22% fat — carb quality (not quantity) is the primary issue. Replacing white rice + maida with millets + whole wheat is the highest-leverage single change for most Indians.