Weight loss and fat loss are not the same thing. If protein intake is too low during a calorie deficit, a portion of what you lose can be muscle instead of fat. This will undermine both your metabolism and your results. Here’s the target that keeps the loss where you want it.
Your Target: 25–30% of Calories, or 1.2–1.6 g/kg Body Weight
During active weight loss, aim for 25–30% of total daily calories from protein, or 1.2–1.6 grams per kilogram of body weight. The lower your calorie intake goes, the more important it is to push toward the top of that range — a smaller calorie budget leaves less wiggle room before protein falls short.
‘Why Protein Matters More in a Deficit
When you eat fewer calories than you burn, your body pulls energy from stored fat. However, it will also break down muscle tissue for fuel if protein intake isn’t enough to signal that muscle should be preserved. This is especially true if the deficit is aggressive or sustained over a long period.
Protein also does more for satiety than fat or carbohydrates, which is arguably just as important: a weight loss plan that leaves you constantly hungry is a plan that’s hard to sustain, regardless of how well-designed the numbers are.
Muscle Preservation Strategies Beyond Protein
Hitting your protein target is the foundation, but it works best combined with:
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- Resistance training. Strength training 2–3x per week gives your body a reason to hold onto muscle even in a calorie deficit — protein alone can slow muscle loss, but resistance training is what actively signals your body to keep it.
- Avoiding overly aggressive deficits. A very large calorie deficit accelerates both fat loss and muscle loss. A moderate, sustainable deficit gives your body more room to preserve lean tissue.
- Distributing protein across the day. Getting 20–30 grams of protein at each of 3–4 meals tends to support muscle maintenance better than getting the same daily total in one or two large servings.
How to Tell If You’re Losing Muscle, Not Just Weight
Scale weight alone can’t tell you what you’re losing. Signs that you may be losing muscle along with fat include feeling noticeably weaker in the gym, decreasing strength on lifts that were previously stable, or a body composition scan showing skeletal muscle mass trending down. If any of these show up, it’s usually a sign to reassess protein intake, training, or the size of the deficit — not to just keep cutting further.
The Bottom Line
Weight loss without a protein strategy risks losing muscle right along with fat. Aim for 25–30% of calories or 1.2–1.6 g/kg, lean toward the top of that range as your calorie intake drops, and pair it with resistance training to make sure the weight you lose comes from where you actually want it to.
Want your exact number? Try our free protein calculator for a personalized target based on your weight and goals.
