Calorie calculator

Understanding calories and energy needs

What are BMR and TDEE?

Basal Metabolic Rate (BMR) is the number of calories your body burns at complete rest to maintain vital functions like breathing, circulation, and cell production. Total Daily Energy Expenditure (TDEE) is your BMR plus calories burned through daily activities and exercise.

Why calorie awareness matters for cancer patients

Maintaining proper nutrition and healthy weight is crucial during and after cancer treatment. Adequate calorie intake helps preserve muscle mass, support immune function, manage treatment side effects, and improve recovery outcomes. Both undernutrition and excess weight can impact treatment effectiveness and overall health.

How the calculator works

This calculator uses the Mifflin-St Jeor equation, one of the most accurate methods for estimating BMR. It factors in age, gender, height, and weight. The TDEE is calculated by multiplying your BMR by an activity factor based on your typical physical activity level.

Activity level definitions

• Sedentary: Little or no exercise, desk job
• Light: Light exercise or sports 1-3 days per week
• Moderate: Moderate exercise 3-5 days per week
• Active: Hard exercise 6-7 days per week
• Very Active: Very intense exercise, physical job, or training twice per day

Calorie needs during cancer treatment

Cancer treatment can significantly affect calorie needs. Chemotherapy, radiation, and surgery increase metabolic demands. Some patients need 20-50% more calories than usual to maintain weight. However, treatment side effects like nausea, taste changes, or loss of appetite can make eating challenging.

Weight management guidelines

For healthy weight change:

• Weight loss: Create a deficit of 500 calories/day for approximately 0.5 kg loss per week
• Weight maintenance: Consume calories equal to your TDEE
• Weight gain: Add 500 calories/day for approximately 0.5 kg gain per week
• During treatment: Prioritize maintaining weight unless your oncology team advises otherwise

Quality matters as much as quantity

Not all calories are equal. Focus on nutrient-dense foods that provide vitamins, minerals, and other beneficial compounds. Emphasize whole grains, lean proteins, fruits, vegetables, and healthy fats. These support immune function and overall health better than empty-calorie processed foods.

Special considerations for cancer survivors

After treatment, maintaining a healthy weight reduces cancer recurrence risk. Research shows that obesity increases the risk of several cancer types returning. Work with your healthcare team to establish appropriate calorie goals that support long-term health and cancer prevention.

When to seek professional help

Consult a registered dietitian or nutritionist if you experience unintended weight loss during treatment, struggle to meet calorie needs, have specific dietary restrictions, or need help creating a personalized nutrition plan. Many cancer centers offer nutrition counseling as part of comprehensive care.

Tips for meeting calorie goals during treatment

• Eat small, frequent meals throughout the day
• Choose calorie-dense foods when appetite is poor
• Add healthy fats like olive oil, nuts, or avocado to increase calories
• Consider nutritional supplements if recommended by your care team
• Stay hydrated, but avoid drinking large amounts before meals
• Eat your largest meal when you feel hungriest