Calorie Deficit Planner

The Science of Fat Loss

Weight loss comes down to energy balance. To lose body fat, you need to consistently consume fewer calories than your body burns. The size of that gap — your calorie deficit — determines how quickly you lose weight.

Choosing Your Deficit

Why Deficits Over 1,000 Calories Are Risky

A deficit greater than 1,000 calories per day might seem like a faster route to your goal, but it often backfires for several reasons:

• Muscle loss — Very large deficits cause your body to break down lean muscle tissue for energy, not just fat. This slows your metabolism and changes your body composition for the worse.
• Metabolic adaptation — Your body responds to extreme restriction by lowering your metabolic rate, making further weight loss progressively harder and increasing the risk of rapid regain.
• Nutrient deficiency — Eating too little makes it nearly impossible to hit your micronutrient needs (vitamins, minerals, fibre), which can affect energy, mood, immunity, and hormone levels.
• Sustainability — The stricter the diet, the harder it is to maintain. Extreme restriction typically leads to binge cycles, frustration, and quitting altogether.