As a Certified Personal Trainer, I am often asked how to start a weight loss program. I like to start with the basics. My first response is, “Get a calculator.”
Losing weight effectively and sustainably requires a scientific approach rather than guesswork. Two of the most important metrics in weight management are your Basal Metabolic Rate (BMR) and Total Daily Energy Expenditure (TDEE). Understanding these can help you set realistic calorie goals and ensure proper macronutrient balance to support your body’s needs.
What is BMR?
BMR represents the number of calories your body needs to maintain basic physiological functions such as breathing, circulation, and cell production while at complete rest. This metric is determined by factors like age, weight, height, and gender.
How to Calculate Your BMR
One of the most widely used formulas for calculating BMR is the Mifflin-St Jeor Equation:
For men:
BMR = (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) + 5
For women:
BMR = (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) – 161
Alternatively, you can use online BMR calculators to get an instant estimate.
What is TDEE?
TDEE represents the total number of calories your body burns in a day, including both your BMR and additional calories burned through daily activities and exercise. This is crucial because it helps determine how many calories you should consume to lose weight.
How to Calculate Your TDEE
To estimate TDEE, multiply your BMR by an activity factor:
- Sedentary (little to no exercise) = BMR × 1.2
- Lightly active (light exercise 1–3 days/week) = BMR × 1.375
- Moderately active (moderate exercise 3–5 days/week) = BMR × 1.55
- Very active (hard exercise 6–7 days/week) = BMR × 1.725
- Super active (intense daily exercise) = BMR × 1.9
Once you determine your TDEE, you can set a calorie deficit to promote weight loss.
Creating a Caloric Deficit for Weight Loss
To lose weight, you need to consume fewer calories than your TDEE. A common approach is:
- 500 calorie deficit per day = ~1 pound of weight loss per week
- 750 calorie deficit per day = ~1.5 pounds of weight loss per week
- 1000 calorie deficit per day = ~2 pounds of weight loss per week
It’s important not to reduce calories too drastically, as this can lead to muscle loss and metabolic slowdown.
Macronutrient Breakdown for Weight Loss
Balancing macronutrients (protein, carbohydrates, and fats) is essential for maintaining energy levels and muscle mass while losing fat.
Protein Intake
Protein is critical for muscle preservation and satiety. Aim for:
- 0.8–1.2 grams per pound of body weight if you engage in regular resistance training.
- 0.6–0.8 grams per pound if you are less active.
Carbohydrates and Fats
The remaining calories should be split between carbohydrates and fats based on personal preference and activity level:
- Higher-carb diets (40–50% of total calories) suit active individuals.
- Lower-carb diets (20–30% of total calories) can be beneficial for those who prefer fat as a primary energy source.
Final Thoughts
Losing weight successfully requires an understanding of your BMR and TDEE, setting the right caloric deficit, and ensuring adequate macronutrient intake. Tracking your food intake and adjusting your diet based on progress will help you stay on the right path. Remember, consistency and patience are key to sustainable weight loss!
