Nutrition and Dietetics
What it is
Unit II is applied nutrition: what the body needs, what goes wrong when it does not get it, and how needs change from conception to old age. It covers assessing individuals and populations, India's policies and programmes, and modifying and counselling diet in disease. UGC-NET favours deficiency signs, cut-offs, assessment methods, programme facts and quick BMI and energy sums.
Core concepts
Food groups, balanced diet and the food pyramid. ICMR's classic five food groups are cereals and millets; pulses; milk, egg and flesh foods; fruits and vegetables; and fats and sugars. A balanced diet supplies every nutrient in the right amounts and proportions, with a margin of safety. A common textbook split is 50-60 per cent of energy from carbohydrate, 10-15 per cent from protein and 20-30 per cent from fat. A food pyramid puts cereals at the base and oils and sugar at the apex; the USDA replaced its pyramid with MyPlate in 2011. Macronutrients are needed in grams and yield energy; micronutrients are needed in milligrams or micrograms.
Role of nutrients. Adults need nine essential amino acids, histidine included. Cereals are limited by lysine and pulses by methionine, so a cereal-pulse mix complements. Protein quality is measured by biological value (N retained / N absorbed × 100), NPU (BV × digestibility), PER (weight gain per gram of protein), PDCAAS and DIAAS. Linoleic (n-6) and alpha-linolenic (n-3) acids are essential. Soluble fibre (pectin, beta-glucan) lowers cholesterol; insoluble fibre (cellulose) adds bulk.
Nutrient deficiencies and requirements for Indians. WHO grades xerophthalmia as night blindness (XN), conjunctival xerosis (X1A), Bitot's spots (X1B), corneal xerosis (X2), keratomalacia (X3) and corneal scar (XS). Thiamine deficiency causes beriberi; riboflavin deficiency causes angular stomatitis. Pellagra (dermatitis, diarrhoea, dementia) is linked to maize and jowar diets, and 60 mg tryptophan yields 1 mg niacin. Folate or B12 deficiency gives megaloblastic anaemia, iron deficiency microcytic anaemia and iodine deficiency goitre. ICMR-NIN 2020 sets EAR, RDA and TUL values on reference weights of 65 kg (men) and 55 kg (women). For adult protein, it sets an EAR of 0.66 g/kg/day and an RDA of 0.83 (as of 2026-10).
Public health nutrition. Public health nutrition prevents diet-related disease across populations. India carries a double burden of undernutrition and overweight or NCDs; hidden hunger makes it a triple burden. In the intergenerational cycle, a baby of low birth weight (under 2,500 g) becomes a stunted girl and then an undernourished mother, so the first 1,000 days matter most. Kwashiorkor has oedema and flaky-paint dermatosis; marasmus is severe wasting without oedema. Gomez grades weight-for-age and Waterlow separates wasting from stunting. In children 6-59 months, WHO defines SAM as weight-for-height below -3 SD, MUAC under 115 mm or bilateral oedema.
Nutrition through the life span. In pregnancy, ICMR-NIN 2020 adds about 350 kcal/day in the second and third trimesters (as of 2026-10). Folic acid around conception prevents neural tube defects. An infant doubles birth weight by about five months and triples it by one year. WHO advises exclusive breastfeeding for six months (colostrum is rich in IgA), then complementary food alongside breastfeeding to two years or beyond. Adolescence brings the growth spurt (earlier in girls) and higher iron and calcium needs. In old age, BMR and lean mass fall (sarcopenia) while calcium, vitamin D and B12 needs rise.
Community, sports and emergency nutrition. Community nutrition uses growth monitoring on the WHO Child Growth Standards (2006) and nutrition education. Endurance athletes use carbohydrate loading and a high-carbohydrate pre-event meal 3-4 hours ahead. They replace about 1.5 L of fluid per kg lost, since losing over 2 per cent of body weight impairs performance, and need 1.2-2.0 g protein/kg. In emergencies, the Sphere planning ration is 2,100 kcal per person per day. SAM is treated with F-75 (75 kcal/100 mL) for stabilisation, then F-100 or RUTF, under CMAM.
Nutritional assessment. Jelliffe's methods are anthropometric, biochemical, clinical and biophysical assessment, dietary surveys, vital statistics and ecological factors. BMI = weight (kg) / height (m) squared. The 2009 Asian-Indian consensus sets normal BMI at 18.0-22.9, overweight at 23.0-24.9 and obese at 25 or above. Its waist cut-offs are 90 cm for men and 80 cm for women. WHO anaemia limits are Hb below 11 g/dL (children 6-59 months, pregnant women), 12 (other women) and 13 (men). Ferritin falls first in iron depletion, and prealbumin (half-life 2-3 days) tracks protein status faster than albumin (about 20 days). Dietary methods are the 24-hour recall, food frequency questionnaire, diet history and weighment (the most accurate).
Nutritional intervention and food security. The National Nutrition Policy dates from 1993. ICDS began on 2 October 1975 with six services: supplementary nutrition, pre-school education, nutrition and health education, immunisation, health check-up and referral. Other programmes are POSHAN Abhiyaan (2018), PM POSHAN (formerly Mid-Day Meal), NIDDCP (1992), vitamin A prophylaxis and Anemia Mukt Bharat (all as of 2026-10). The NFSA 2013 gives 5 kg of grain per person per month and 35 kg per Antyodaya household. Food security has four pillars: availability, access, utilisation and stability. Nutrition security adds health and care. Fortification includes iodised and double-fortified salt.
Clinical and therapeutic nutrition. Therapeutic diets modify consistency (clear fluid, full fluid, soft), energy, nutrients or fibre. If the gut works, use it: enteral feeding (nasogastric, PEG) comes before parenteral (TPN), and refeeding risks hypophosphataemia. Diabetes is diagnosed by fasting glucose of 126 mg/dL or more, 2-h OGTT of 200 or more, or HbA1c of 6.5 per cent or more. Its diet uses exchanges and low glycaemic index (55 or below). For hypertension, WHO advises under 5 g salt/day. Coeliac disease needs a gluten-free diet, PKU restricts phenylalanine, galactosaemia removes lactose and gout limits purines.
Diet counselling and management. The Nutrition Care Process has four steps: assessment, diagnosis (a PES statement: problem, etiology, signs and symptoms), intervention, and monitoring and evaluation. Counselling may be directive, non-directive (Rogers) or eclectic. It draws on motivational interviewing and on the stages of change: precontemplation, contemplation, preparation, action and maintenance.
Research methods: designs, principles and purpose. Research aims to explore, describe, explain, predict or evaluate. The randomised controlled trial is the experimental gold standard; quasi-experiments lack randomisation. Cross-sectional studies give prevalence. Case-control studies start from the outcome and yield an odds ratio. Cohort studies follow exposure forward and yield relative risk. Good designs secure validity, reliability and control of confounding.
Worked example
BMI, energy need and a reducing diet. A sedentary woman aged 25 weighs 60 kg and is 1.58 m tall.
| Step | Working | Result |
|---|---|---|
| Height squared | 1.58 × 1.58 | 2.4964 m² |
| BMI | 60 / 2.4964 | 24.0 kg/m² |
| BMR (FAO/WHO/UNU, women 18-30) | 14.7 × 60 + 496 = 882 + 496 | 1,378 kcal |
| Energy need (PAL 1.53) | 1,378 × 1.53 | 2,108 kcal |
| Reducing diet (-500 kcal/day) | 2,108 - 500 | 1,608 kcal |
| Protein (0.83 g/kg) | 0.83 × 60 = 49.8 g, about 50 g × 4 | 200 kcal |
| Fat (25% of energy) | 1,608 × 0.25 = 402 kcal, / 9 | about 45 g |
| Carbohydrate (rest) | 1,608 - 200 - 402 = 1,006 kcal, / 4 | about 251 g |
Check: 24.0 × 2.4964 = 59.9, which matches 60 kg. 1,378 × 1.5 = 2,067, plus 1,378 × 0.03 = 41, gives 2,108. The parts sum back: 200 + 402 + 1,006 = 1,608. A BMI of 24.0 is normal by WHO (18.5-24.9) but overweight by the Asian-Indian cut-offs (23.0-24.9).
Common traps
- Kwashiorkor has oedema and marasmus does not.
- Cereals lack lysine and pulses lack methionine, not the reverse.
- Asian-Indian BMI cut-offs (23 and 25) are not the WHO ones (25 and 30).
- Case-control studies run back from outcome (odds ratio); cohort studies run forward from exposure (relative risk).
- Bitot's spots are X1B, not corneal xerosis (X2).
Speed technique
- For BMI, square the height once, divide, then multiply back to check.
- Energy need = BMR × PAL; split it at 4, 4 and 9 kcal/g, with carbohydrate taking the remainder.
- Remember SAM as a triad: below -3 SD, under 115 mm and oedema.
- Pellagra follows maize: its niacin is bound and it is low in tryptophan.
Check yourself
- What is the BMI of a woman of 60 kg and 1.58 m, and how is it classed for Asian Indians?
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About 24.0, overweight: 60 / 2.4964, within 23.0-24.9. - Which amino acid limits cereal protein?
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Lysine: pulses complement it. - What MUAC marks severe acute malnutrition at 6-59 months?
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Below 115 mm: or WHZ below -3 SD, or oedema. - Which iron index falls first as stores deplete?
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Serum ferritin: haemoglobin falls last. - Which design starts from cases and controls and looks back at exposure?
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Case-control: it yields an odds ratio.
Try it: Nutrition and Dietetics questions
Real questions from the NET Home Science bank on exactly this skill. Pick an answer to see the full solution — the intuition, the worked steps, the faster methods and the traps.
Using the FAO/WHO/UNU equation for men aged 18–30 years, BMR (kcal/day) = 15.3 × weight (kg) + 679, what is the BMR of a 25-year-old man weighing 70 kg?
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Answer: option B
The weight term is 15.3 × 70 = 1,071 kcal, since 15 × 70 = 1,050 and 0.3 × 70 = 21.
Adding the constant gives 1,071 + 679 = 1,750 kcal/day, and the check = 70 kg recovers the weight.
So the man's BMR is 1,750 kcal/day, option B.
Applying the ICMR-NIN 2020 adult protein RDA of 0.83 g per kg body weight per day, the daily protein requirement of a woman weighing 55 kg is about:
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Answer: option C
ICMR-NIN 2020 sets the adult protein RDA at 0.83 g per kg body weight per day, above the EAR of 0.66 g/kg (as of 2026-10).
For a 55 kg woman, 0.83 × 55 = 45.65 g, which is about 46 g of protein a day.
So her protein requirement is about 46 g a day, option C.
Consider the following two statements: Statement I: A healthy infant roughly doubles its birth weight by about five months of age. Statement II: A healthy infant roughly triples its birth weight only by about two years of age. In the light of the above statements, choose the correct answer from the options.
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Answer: option C
Statement I: a healthy infant doubles its birth weight by about five months; Statement I is true.
Statement II: the birth weight is tripled by about one year of age, not two; Statement II is false.
So Statement I, "A healthy infant roughly doubles its birth weight…", is true and Statement II is false, option C.
A 1,800 kcal diet is planned with 15 per cent of energy from protein and 25 per cent from fat, carbohydrate supplying the rest. Using 4, 4 and 9 kcal/g for protein, carbohydrate and fat, the diet provides about:
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Answer: option B
Protein supplies 0.15 × 1,800 = 270 kcal and fat 0.25 × 1,800 = 450 kcal, so fat is = 50 g.
Carbohydrate supplies the rest, 1,800 − 270 − 450 = 1,080 kcal, or 1, = 270 g, and the parts sum back to 270 + 450 + 1,080 = 1,800 kcal.
So the diet provides about 50 g fat and 270 g carbohydrate, option B.
Read the following Assertion (A) and Reason (R) and choose the correct answer from the given options: Assertion (A) : Populations that depend heavily on maize are prone to pellagra. Reason (R) : Maize is rich in available niacin and in tryptophan.
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Answer: option C
Assertion: pellagra, with its dermatitis, diarrhoea and dementia, has long been associated with maize-based diets (and with jowar in India); the assertion is true.
Reason: maize is low in tryptophan, from which the body makes niacin (60 mg tryptophan gives 1 mg niacin), and much of its niacin is bound and unavailable; the reason is false.
So the assertion "Populations that depend heavily on maize…" is true but (R) is false, option C.
Answer above — every one shows its working.