The One Rule of Weight Loss

If you're feeling overwhelmed by conflicting diet advice, it helps to simplify. The endless debate over keto, paleo, fasting, and vegan diets all boils down to one fundamental law of thermodynamics: the calorie deficit.

To lose body fat, you must consume fewer calories than your body expends. That's it. It's the one non-negotiable rule. Any diet that results in weight loss does so by helping you achieve a calorie deficit.

What Is a Calorie Deficit?

Think of your body's energy needs like a budget.

Calories In: The energy you consume from food and drink.
Calories Out (TDEE): Your Total Daily Energy Expenditure. This is the total number of calories your body burns in a day through basic bodily functions (BMR), daily activity, and exercise.

A calorie deficit occurs when your "Calories In" are less than your "Calories Out." When this happens, your body needs to find energy from another source. It turns to its stored energy reserves—primarily body fat—to make up the difference.

Finding Your Sustainable Deficit

The key word here is sustainable. A massive deficit might lead to rapid initial weight loss, but it's often unsustainable and leads to muscle loss, fatigue, and eventual rebound weight gain.

A moderate and intelligent approach is better.

Start Small: A deficit of 300-500 calories below your TDEE is a great starting point. This typically leads to a safe and sustainable loss of about 0.5-1 lb (0.25-0.5 kg) per week.
Prioritize Protein: When in a deficit, getting enough protein is crucial. It helps you feel full and signals your body to preserve muscle mass, ensuring you're losing fat, not muscle.
Include Resistance Training: Lifting weights tells your body that your muscle is essential and needs to be kept, further encouraging it to burn fat for fuel.

It's a Journey, Not a Race

Remember, your body is smart and will adapt. As you lose weight, your TDEE will decrease slightly, and you may need to adjust your intake or increase your activity to continue making progress. This is normal.

The most important thing is to find a system that works for you. Don't focus on extreme restrictions. Instead, focus on creating a consistent, moderate deficit through a balanced diet and regular activity. This is the path to not just losing weight, but keeping it off for good.