Estimating daily calorie (energy) needs is a starting point for understanding nutritional requirements. The figures below are based on widely used formulas and population-level data. Individual needs can vary significantly based on genetics, body composition, health status and other factors.
Basal Metabolic Rate (BMR)
BMR represents the number of calories your body requires at rest to maintain basic physiological functions. The Mifflin-St Jeor equation is one of the most commonly used formulas for estimating BMR:
Men: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age in years) + 5
Women: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age in years) − 161
Total Daily Energy Expenditure (TDEE)
TDEE is estimated by multiplying BMR by an activity factor. This provides an approximate daily calorie need.
| Activity Level | Description | Multiplier |
|---|---|---|
| Sedentary | Little or no exercise, desk job | BMR × 1.2 |
| Lightly active | Light exercise 1–3 days per week | BMR × 1.375 |
| Moderately active | Moderate exercise 3–5 days per week | BMR × 1.55 |
| Very active | Hard exercise 6–7 days per week | BMR × 1.725 |
| Extra active | Very hard exercise, physical job or training twice daily | BMR × 1.9 |
Example Calculations
The following are hypothetical examples for illustration purposes only.
| Profile | Estimated BMR | Activity Level | Estimated TDEE |
|---|---|---|---|
| Male, 30 yrs, 80 kg, 178 cm | ~1,780 kcal | Moderately active | ~2,759 kcal |
| Female, 28 yrs, 65 kg, 165 cm | ~1,421 kcal | Lightly active | ~1,954 kcal |
| Male, 45 yrs, 90 kg, 180 cm | ~1,805 kcal | Sedentary | ~2,166 kcal |
| Female, 35 yrs, 58 kg, 160 cm | ~1,289 kcal | Very active | ~2,224 kcal |
Macronutrient Reference Ranges
The Australian Dietary Guidelines suggest the following Acceptable Macronutrient Distribution Ranges (AMDR) for adults:
| Macronutrient | AMDR (% of total energy) | Calories per gram |
|---|---|---|
| Protein | 15–25% | 4 kcal/g |
| Fat | 20–35% | 9 kcal/g |
| Carbohydrates | 45–65% | 4 kcal/g |
These ranges provide flexibility to accommodate individual preferences and dietary patterns. There is no single "ideal" macronutrient ratio for all people.
Calorie Content of Common Foods
The following are approximate values per standard serving:
| Food Item | Serving Size | Approximate Calories |
|---|---|---|
| Chicken breast (cooked) | 100 g | 165 kcal |
| Brown rice (cooked) | 1 cup (195 g) | 218 kcal |
| Broccoli (steamed) | 1 cup (156 g) | 55 kcal |
| Banana | 1 medium (118 g) | 105 kcal |
| Whole egg (boiled) | 1 large (50 g) | 78 kcal |
| Greek yoghurt (plain, low-fat) | 170 g | 100 kcal |
| Salmon fillet (cooked) | 100 g | 208 kcal |
| Rolled oats (dry) | ½ cup (40 g) | 150 kcal |
| Avocado | ½ medium (68 g) | 114 kcal |
| Sweet potato (baked) | 1 medium (130 g) | 103 kcal |