Hong Life CalculatorsUnderstanding the refeed day calculator — concept and principle
A refeed day is a planned day during a diet when you eat at maintenance, with the extra calories coming mostly from carbohydrate. This calculator sets protein and fat from your body weight and gives the rest of your maintenance calories to carbohydrate.
How it is calculated
- Protein (g) = weight (kg) × protein per kg.
- Fat (g) = weight (kg) × fat per kg.
- Refeed carbs (g) = (TDEE − protein g × 4 − fat g × 9) ÷ 4.
- Refeed calories = your maintenance calories (TDEE).
Protein and carbohydrate provide 4 kcal per gram, fat 9 kcal per gram.
The principle
Long calorie deficits lower muscle glycogen and are associated with drops in leptin and other signals of energy availability. Carbohydrate refills glycogen directly, and in short-term studies overfeeding carbohydrate raised leptin and energy expenditure more than overfeeding fat. Keeping protein steady protects muscle, and keeping fat low leaves room for carbohydrate without going above maintenance. The main practical effects reported by dieters are better training performance and an easier time sticking to the diet; any metabolic boost lasts only a short time.
Worked example
- Inputs: weight 75 kg, TDEE 2,500 kcal, protein 2 g/kg, fat 0.6 g/kg.
- Protein = 75 × 2 = 150 g (600 kcal).
- Fat = 75 × 0.6 = 45 g (405 kcal).
- Carbohydrate = (2,500 − 600 − 405) ÷ 4 = 1,495 ÷ 4 = 373.75, shown as 374 g.
- Refeed calories = 2,500 kcal.
| Maintenance calories (TDEE) | Refeed carbs (g) |
|---|---|
| 625 | -95 |
| 1,250 | 61 |
| 1,875 | 218 |
| 2,500 | 374 |
| 3,125 | 530 |
| 3,750 | 686 |
| 5,000 | 999 |
How to read the result
About 4.5–5 g of carbohydrate per kg body weight, as here, is typical for a refeed. Lean, very active people dieting hard tend to benefit most and may refeed once a week or more; people with more body fat or a small deficit often do not need refeeds at all. Expect the scale to rise 0.5–1.5 kg the next morning from glycogen and water. This is not fat and usually falls back within a few days.
Common mistakes
- Turning a refeed into an unplanned cheat day with high fat, which adds calories without refilling glycogen better.
- Using an inflated TDEE, which makes the refeed a surplus.
- Judging fat loss from the weigh-in the morning after a refeed.
Frequently asked questions
How often should I do a refeed?
It depends on leanness and deficit size: from once a week or more for very lean athletes to rarely or never for people early in a diet.
Which carbs are best?
Starchy, low-fat foods such as rice, potatoes, bread, oats and fruit refill glycogen well and keep fat low.
Is a refeed the same as a diet break?
No. A refeed lasts one or two days; a diet break is a week or more at maintenance.
Sources: Trexler ET, Smith-Ryan AE, Norton LE. Metabolic adaptation to weight loss: implications for the athlete. Journal of the International Society of Sports Nutrition 2014. · Helms ER, Aragon AA, Fitschen PJ. Evidence-based recommendations for natural bodybuilding contest preparation: nutrition and supplementation. Journal of the International Society of Sports Nutrition 2014.