IIFYM

IIFYM (If It Fits Your Macros) is a dieting philosophy where food choices are unrestricted as long as your daily intake matches your target grams of fat, protein, and carbohydrates. Rather than following a fixed list of allowed foods (as diets like keto or paleo do), IIFYM treats any food as fair game provided the macro totals for the day come out right.

The approach still requires calculating a calorie target and macro split, the same underlying process used by more restrictive diets — the difference is in food selection freedom, not in the calculation itself. The IIFYM Calculator sets these targets using the same logic as the Keto Calculator, just without a forced high-fat ratio.

Calories from each macro = Total daily calories × macro percentage

Grams of fat = Fat calories ÷ 9 Grams of protein or carbs = Calories ÷ 4

Macro percentages under IIFYM are flexible and commonly set based on goal (fat loss, muscle gain, maintenance) rather than a fixed ketogenic ratio.

For a 2,200-calorie target with a 30% protein / 35% fat / 35% carb split:

• Protein: 2,200 × 0.30 = 660 calories ÷ 4 = 165g protein
• Fat: 2,200 × 0.35 = 770 calories ÷ 9 = 86g fat
• Carbs: 2,200 × 0.35 = 770 calories ÷ 4 = 193g carbs

• Flexibility doesn't mean unlimited freedom in practice: hitting daily protein and micronutrient needs still generally requires prioritising whole foods most of the time.
• Start from a calorie target, not macros directly: use the TDEE Calculator first, then set macro percentages from that baseline.
• Different from keto: IIFYM doesn't force a specific carb ceiling, so it doesn't guarantee ketosis the way a strict keto macro split does.
• Works for any goal: the same IIFYM framework applies whether the goal is fat loss, muscle gain, or maintenance — only the percentage split changes.