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The science

How we calculate

Every number in Food Cheater comes from published research or official health guidance. Here is how each one is worked out, and where it comes from.

Food Cheater provides nutritional guidance and calorie estimates for educational and fitness purposes only. It is not medical advice. Consult a healthcare professional before starting any new diet or fasting protocol.

1. What your body burns at rest

We start with your resting burn: the calories your body uses in a day just to keep you alive. We use the Mifflin–St Jeor equation, which a systematic review found to be the most reliable of the common equations.

Men: 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5
Women: 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161
If you choose "Other", we use the midpoint of the two: − 78
Sources
  • Mifflin MD, St Jeor ST et al. A new predictive equation for resting energy expenditure in healthy individuals. American Journal of Clinical Nutrition, 1990. pubmed.ncbi.nlm.nih.gov/2305711
  • Frankenfield D et al. Comparison of predictive equations for resting metabolic rate in healthy nonobese and obese adults: a systematic review. Journal of the American Dietetic Association, 2005. pubmed.ncbi.nlm.nih.gov/15883556

2. What you burn in a day

Your resting burn is multiplied by your activity level. These are the standard activity factors used in clinical nutrition.

No workouts a week× 1.2
1–2 workouts a week× 1.375
3–5 workouts a week× 1.55
6 or more workouts a week× 1.725

3. Your daily calorie target

To lose weight, we take a set amount off your daily burn, based on the pace you choose. One kilogram of body fat holds about 7,700 calories, so:

daily reduction = pace (kg per week) × 7,700 ÷ 7
0.25 kg a week275 calories less a day
0.5 kg a week550 calories less a day
0.75 kg a week825 calories less a day
0.9 kg a week990 calories less a day (the fastest we allow)

To maintain, your target is your daily burn. To gain weight we add 500 calories a day; to build muscle, 250.

The 7,700 figure is a good guide but not exact. As you lose weight, your body burns a little less. That's why Food Cheater recalculates your target every time you log your weight.

Sources

4. Safe pace and our safety floor

You choose how fast to lose weight, up to 0.9 kg (about 2 lb) a week. That's the top of the range the US National Institutes of Health recommend: a deficit of 500 to 1,000 calories a day, to lose 1 to 2 lb a week. Losing faster doesn't give a better result after a year.

However fast a pace you choose, your target never drops below 1,200 calories a day for women, or 1,500 for men (and if you choose "Other"). The NIH guidelines give 1,000–1,200 calories a day for women and 1,200–1,500 for men, so our floor sits at the top of each range, on the safe side.

Sources
  • National Heart, Lung, and Blood Institute (NIH). Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults: The Evidence Report, Chapter 4, Treatment Guidelines. NIH Publication No. 98-4083, 1998. ncbi.nlm.nih.gov/books/NBK2004
  • Same guidelines, Summary of Recommendations. ncbi.nlm.nih.gov/books/NBK1989

5. Protein, carbs and fat

Your calories are split 40% carbs, 30% protein and 30% fat. On a high-protein plan, protein is set at 1.6 g per kg of your body weight, the level research links to the best muscle gains. On low-carb, the carb and fat shares swap. Protein and carbs have 4 calories per gram; fat has 9.

Sources
  • National Academies. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. nap.nationalacademies.org/catalog/10490
  • Morton RW et al. A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. British Journal of Sports Medicine, 2018. pubmed.ncbi.nlm.nih.gov/28698222

6. Fibre, sugar, saturated fat and salt

Fibreat least 14 g for every 1,000 calories you eat
Sugarno more than 10% of your calories
Saturated fatno more than 10% of your calories
Sodiumno more than 2,300 mg a day
Sources

7. Water

Your daily water goal is 35 ml for every kg of body weight, kept within the healthy range for your sex: 1.6 to 2.2 litres for women, 2 to 3 litres for men.

Sources

8. Calories from activity

Each activity you log has an energy value from the 2024 Adult Compendium of Physical Activities, the standard reference used by researchers.

calories = energy value × 3.5 × your weight (kg) ÷ 200 × minutes

Steps count once you pass 5,000 a day, the point research uses to mark a sedentary day. Below that, your everyday movement is already part of your daily burn. Above it, we use the distance you walked: about 0.5 calories per kg of body weight for every kilometre (the American College of Sports Medicine walking equation).

Sources
  • Compendium of Physical Activities. pacompendium.com
  • Herrmann SD et al. 2024 Adult Compendium of Physical Activities: A third update of the energy costs of human activities. Journal of Sport and Health Science, 2024. pubmed.ncbi.nlm.nih.gov/38242596
  • Tudor-Locke C et al. A step-defined sedentary lifestyle index: <5000 steps/day. Applied Physiology, Nutrition, and Metabolism, 2013. pubmed.ncbi.nlm.nih.gov/23438219

9. Healthy weight check

If a goal weight would take you below a body mass index (BMI) of 18.5, the World Health Organization's line for underweight, Food Cheater won't set it.

Source