Empty calories are calories from foods that provide energy (calories) but little or no nutritional value - few vitamins, minerals, proteins, or fibre. Examples include soft drinks, alcohol, candy, chips, white sugar, and processed snacks. These contribute to obesity and nutrient deficiencies while displacing nutritious foods. A diet high in empty calories is a major risk factor for chronic disease.

According to ICMR-NIN Dietary Guidelines for Indians, a balanced diet for an adult should include: Cereals (rice, wheat, millets) for energy, Pulses and legumes for protein, Vegetables and fruits for vitamins, minerals, and fibre, Dairy or dairy alternatives for calcium, Small amounts of fats and oils for fat-soluble vitamins and essential fatty acids, and Adequate water. The guidelines recommend eating a rainbow of colourful vegetables and fruits and limiting salt, sugar, and processed foods.

Unsaturated fats (monounsaturated and polyunsaturated) are generally liquid at room temperature and found primarily in plant oils (olive, sunflower, mustard) and fish. They are considered heart-healthy - they lower LDL (bad cholesterol) and raise or maintain HDL (good cholesterol). Saturated fats (butter, ghee, red meat) are solid at room temperature and raise LDL cholesterol.

Vitamin B9 (Folic Acid/Folate) is essential for: DNA synthesis and repair, Cell division - especially during rapid growth (pregnancy, infancy), Red blood cell formation, and Prevention of Neural Tube Defects (Spina Bifida) in early pregnancy. It works closely with Vitamin B12. Deficiency causes Megaloblastic Anaemia and Neural Tube Defects. Women planning pregnancy are advised to take 400 mcg/day of folic acid.

Fluoride protects teeth by: Incorporating into tooth enamel (as fluorapatite), making it harder and more resistant to acid, Inhibiting bacteria that cause dental caries, and Remineralising early cavities. Controlled fluoridation of drinking water (0.5-1 ppm) is a major public health measure. However, excess fluoride (above 1.5 ppm) causes dental and skeletal fluorosis. Sources: fluoridated water, toothpaste, tea, seafood.

Saturated fats are found mainly in animal products (butter, ghee, red meat, full-fat dairy) and some tropical oils (coconut oil, palm oil). Excess consumption raises LDL (bad cholesterol) levels, increasing risk of atherosclerosis, heart disease, and stroke. Health guidelines recommend limiting saturated fat to less than 10% of total daily calorie intake and replacing with unsaturated fats.

Antioxidants neutralize free radicals - unstable molecules that damage cells, proteins, and DNA through oxidative stress. Oxidative stress is linked to ageing, cancer, heart disease, and neurodegeneration. Key dietary antioxidants include: Vitamin C, Vitamin E, Beta-carotene, Selenium, Zinc, and polyphenols found in fruits, vegetables, tea, and dark chocolate.

Vitamin D deficiency causes: Rickets in children - soft, weak, deformed bones, bowed legs, dental problems, Osteomalacia in adults - bone pain, muscle weakness, fractures, and Osteoporosis - reduced bone density in elderly. Vitamin D is essential for intestinal calcium and phosphorus absorption. Without adequate Vitamin D, bones cannot mineralize properly. Sources: sunlight (primary), cod liver oil, fatty fish, egg yolks, fortified milk.

Night blindness is caused by Vitamin A deficiency. Carrots and leafy greens (spinach, kale, sweet potato) are rich in Beta-carotene - a provitamin A that is converted to Vitamin A in the body. Animal sources like liver, egg yolk, and dairy provide preformed Vitamin A (Retinol) directly. Regular consumption prevents night blindness and xerophthalmia.

Vitamin C significantly enhances non-heme iron absorption (plant sources) by: Reducing Fe3+ (ferric) to Fe2+ (ferrous) form which is more easily absorbed, and Forming a soluble iron-Vitamin C complex that resists inhibitors. Therefore, eating iron-rich foods (spinach, lentils, fortified cereals) alongside Vitamin C sources (lemon juice, tomatoes, amla) dramatically improves iron absorption and prevents Iron Deficiency Anaemia.