Nutrition — Key Concepts and Q&A
Core Concepts
Q: Macronutrients — what they are and how much you need.
Carbohydrates (4 kcal/g): Primary energy source. Brain runs almost exclusively on glucose.
•Simple: sugars (glucose, fructose, lactose) — fast energy, spikes blood sugar
•Complex: starch, fibre — slow digestion, stable blood sugar
•Recommended: 45-65% of total calories. Emphasis on whole grains, vegetables, legumes.
•Fibre: 25-38g/day. Feeds gut bacteria, regulates blood sugar, bowel health.
Proteins (4 kcal/g): Building blocks (amino acids). Muscle, enzymes, hormones, immune function.
•Essential amino acids (9): must come from diet (cannot synthesise)
•Complete proteins: all essential AAs — meat, fish, eggs, dairy, quinoa, soy
•Recommended: 0.8g/kg body weight (sedentary). 1.2-2.2g/kg for athletes.
•Higher intake supports muscle retention, satiety, metabolic rate.
Fats (9 kcal/g): Energy storage, hormones, fat-soluble vitamins (A,D,E,K), cell membranes.
•Saturated: animal fats, coconut oil — moderate intake
•Unsaturated: nuts, seeds, avocado, olive oil — cardioprotective
•Omega-3 (EPA, DHA): anti-inflammatory, brain health — fatty fish, flaxseed, walnuts
•Trans fats: industrial (partially hydrogenated oils) — avoid completely
•Recommended: 20-35% of calories. Avoid trans fats; limit saturated.
Q: Micronutrients — key vitamins and minerals.
| Nutrient | Key Function | Sources | Deficiency |
|---|
|---|---|---|---|
| Vitamin D | Bone, immunity, mood | Sunlight, fortified foods, fatty fish | Rickets, immune dysfunction |
|---|
| Vitamin B12 | Nerve function, RBC formation | Meat, dairy, eggs (vegans supplement) | Anemia, nerve damage |
| Iron | Haemoglobin (carries oxygen) | Red meat, lentils, spinach + vitamin C | Anemia, fatigue |
| Calcium | Bone, muscle, nerve | Dairy, leafy greens, tofu | Osteoporosis |
| Iodine | Thyroid hormones | Iodised salt, seafood | Goitre, hypothyroidism |
| Zinc | Immunity, wound healing | Meat, shellfish, seeds | Poor wound healing |
| Magnesium | 300+ enzyme reactions | Nuts, seeds, whole grains | Muscle cramps, fatigue |
| Folate (B9) | DNA synthesis, fetal development | Leafy greens, legumes | Neural tube defects (pregnancy) |
| Vitamin C | Collagen, immunity, antioxidant | Citrus, bell peppers, amla | Scurvy |
Q: Balanced diet frameworks.
Harvard Healthy Eating Plate:
•½ plate: vegetables and fruits (variety of colours)
•¼ plate: whole grains (oats, brown rice, whole wheat)
•¼ plate: protein (fish, poultry, beans, nuts, eggs)
•Side: healthy oils (olive, mustard, groundnut)
•Water/unsweetened drinks. Limit red meat, processed foods, sugary drinks.
Indian dietary context:
•Traditional Indian diet can be nutritionally complete: dal-chawal-sabzi-roti combination provides complete nutrition
•Concern: low vitamin D (despite sun), B12 (vegetarian population), iron (women)
•Challenge: ultra-processed foods, maida (refined flour), excessive ghee/oil, high salt
Q: Reading nutrition labels.
Serving size: everything is per serving (may be misleading — check servings per pack)
Calories: total energy per serving
Nutrients to LIMIT: Nutrients to GET ENOUGH:
Saturated fat (<10% DV) Fibre (≥20% DV = good source)
Trans fat (0g ideally) Vitamins (A, C, D, calcium, iron)
Sodium (<2300mg/day) Protein
Added sugars (<10% DV)
% Daily Value: based on 2000 kcal diet
5% or less = low | 20% or more = high
Ingredients list: listed by weight (descending)
First ingredient is most. Sugar hidden as: dextrose, fructose, corn syrup, maltose.
Q: Nutrition myths — evidence vs misinformation.
Myth: Carbs are bad.
Fact: Refined carbs (white bread, sugary drinks) are problematic. Whole food carbs (vegetables, legumes, whole grains) are associated with better health outcomes.
Myth: Fat makes you fat.
Fact: Excess calories of any macronutrient cause fat gain. Healthy fats are essential. Low-fat foods often add sugar to compensate.
Myth: You need to detox.
Fact: Liver and kidneys continuously detoxify. No scientific evidence for "detox" products. Eating whole foods, staying hydrated, and sleeping supports natural detoxification.
Myth: Protein supplements are necessary.
Fact: Most people can meet protein needs through food. Supplements convenient but not essential unless food intake is insufficient.
Revision Notes
MACRONUTRIENTS:
Carbs (4 kcal/g): 45-65% calories. Complex > simple. Fibre 25-38g/day.
Protein (4 kcal/g): 0.8g/kg (sedentary), 1.2-2.2g/kg (athletes). Complete proteins.
Fat (9 kcal/g): 20-35% calories. Omega-3 anti-inflammatory. No trans fats.
KEY MICRONUTRIENTS:
Vitamin D: sunlight (Indians often deficient) | B12: vegans must supplement
Iron: women risk (menstruation) | Folate: critical in pregnancy
Calcium: dairy/leafy greens | Iodine: iodised salt
HEALTHY PLATE: 1/2 veggies+fruit | 1/4 whole grains | 1/4 protein | healthy fats
Indian diet: dal-chawal-sabzi is nutritionally sound base
NUTRITION LABELS: serving size check | 5% DV=low, 20%=high | ingredients by weight
Sugar hiding: dextrose, fructose, corn syrup, maltose
MYTHS: Carbs are bad (false) | Fat makes fat (false) | Detox needed (false)
Evidence: whole foods diet consistently best across populations
