Frequently Asked Questions

The calculator uses the Mifflin-St Jeor formula, which research shows has an average margin of error of about 10% for healthy adults. This means if your result is 2000 kcal, your true maintenance is likely between 1800–2200 kcal. Use the result as a starting point, eat at that level for 2–3 weeks, then adjust by 100–150 kcal based on whether your weight is going up, down, or staying stable.

BMR (Basal Metabolic Rate) is the number of calories your body burns at complete rest — just to keep you alive. It accounts for breathing, circulation, cell repair, and temperature regulation. BMR typically makes up 60–75% of your total daily calorie burn. Our calculator uses the Mifflin-St Jeor equation to estimate it.

TDEE (Total Daily Energy Expenditure) is your total calorie burn per day, including physical activity. It's calculated by multiplying your BMR by an activity factor. TDEE is the key number for nutrition planning — eating at TDEE maintains weight, eating below it causes fat loss, and eating above it causes weight gain.

Most people underestimate their activity level. Here is a guide: Sedentary — desk job, no intentional exercise; Lightly active — 1–3 workouts per week or a job that involves some walking; Moderately active — 3–5 workouts per week; Very active — 6–7 workouts per week or a physically demanding job; Extremely active — hard daily training plus a physical job. If in doubt, choose one level lower than you think — it is easier to eat more than to cut back.

Different calculators use different formulas (Harris-Benedict, Katch-McArdle, Mifflin-St Jeor) and different activity multipliers. A difference of 100–200 kcal between calculators is completely normal. Our calculator uses Mifflin-St Jeor which is considered the most accurate for the general population. All results are estimates — real-world results over 2–3 weeks are the most reliable guide.

A deficit of 300–500 calories below your TDEE produces fat loss of approximately 0.3–0.5 kg per week — a sustainable and evidence-based rate. Larger deficits (700+ kcal) speed up weight loss but increase muscle loss and are harder to maintain. The minimum recommended intake is 1200 kcal for women and 1500 kcal for men — going below this without medical supervision is not advisable.

The most common reasons are: 1) underestimating calorie intake — research shows people typically underestimate by 20–40%, often by miscounting cooking oils, sauces, and drinks; 2) overestimating calorie burn from exercise; 3) water retention masking fat loss, especially around menstruation or after starting a new exercise programme; 4) the deficit is too small. Using a food scale for 2–3 weeks often reveals hidden calories.

A surplus of 200–350 calories above your TDEE is the evidence-based recommendation for lean muscle gain. This produces approximately 0.2–0.5 kg of weight gain per week, most of which should be muscle with adequate protein and resistance training. Larger surpluses do not build muscle faster — they only increase fat gain. Beginners can sometimes gain muscle even in a small deficit.

Yes — all calories count regardless of source. Drinks are one of the most underestimated sources: a latte can have 150–300 kcal, a glass of orange juice 110 kcal, a beer 150–200 kcal, and a smoothie 300–500 kcal. Liquid calories are particularly easy to overconsume because they don't trigger the same satiety signals as solid food. Tracking drinks is often where the most 'hidden' calories are found.

For active people, the evidence-based recommendation is 1.6–2.2g of protein per kg of body weight per day. The higher end (2–2.4g/kg) is recommended when in a calorie deficit to preserve muscle mass. The official RDA of 0.8g/kg is the minimum to prevent deficiency in sedentary people, not an optimal intake for active individuals.

No — carbohydrates are not inherently bad. They are the body's preferred fuel for high-intensity exercise and essential for brain function. The type and quantity matter more than the presence of carbs: whole grain, fibre-rich, and low-GI sources (oats, vegetables, legumes, fruit) support health and satiety, while highly processed sources with added sugar offer little nutritional value. Weight gain comes from total excess calories, not carbs specifically.

Fat is essential for hormone production, vitamin absorption, and cell function. The general recommendation is 0.7–1g of fat per kg of body weight per day, which typically equates to 20–35% of total calories. Going too low in fat (below 15% of calories) can impair hormone function and vitamin absorption. Prioritise unsaturated fats from sources like olive oil, nuts, avocado, and fatty fish.

For fat loss, tracking calories alone is often sufficient. For muscle building or body recomposition, tracking protein in addition to calories makes a meaningful difference. Full macro tracking (protein, carbs, fat) gives the most control over body composition but is also the most demanding. A practical approach: track calories and protein, and let fat and carbs fill in the remaining calories as preferred.

BMI (Body Mass Index) categories: Underweight = below 18.5, Normal weight = 18.5–24.9, Overweight = 25–29.9, Obese = 30 and above. BMI is a useful population-level screening tool but has limitations for individuals — it does not account for muscle mass, bone density, or fat distribution. Athletes often have high BMIs due to muscle, while some people with normal BMIs can have high body fat percentages.

General guidelines suggest 35ml per kg of body weight per day as a baseline — approximately 2–2.5 litres for most adults. This increases with exercise (add 500ml per hour of training), hot weather, and high-protein diets. Thirst is generally a reliable guide for healthy adults, though older adults and athletes may need to drink proactively. Our Water Intake Calculator gives a personalised estimate.

Healthy ranges vary by gender: For women — Essential fat: 10–13%, Athletic: 14–20%, Fitness: 21–24%, Acceptable: 25–31%. For men — Essential fat: 2–5%, Athletic: 6–13%, Fitness: 14–17%, Acceptable: 18–24%. Body fat above 32% for women and 25% for men is associated with increased health risks. Use our Body Fat Calculator for an estimate.

Our meal plans are designed as sample templates for healthy adults. The calorie levels (1600/2100/2800 kcal) are approximate averages — your actual needs depend on your height, weight, age, gender, and activity level. Use our Calorie Calculator to find your personal target, then scale meal portions up or down to match. People with medical conditions, food allergies, or specific dietary requirements should consult a registered dietitian.