Calories Explained: Frequently Asked Questions

A calorie is simply a unit of energy. Scientifically, it's the amount of heat energy needed to raise the temperature of one gram of water by one degree Celsius. In nutrition, it represents the energy your body gets from the food and drink you consume.

This depends on your age, gender, height, weight, and activity level. On average, adult women need 1,600–2,400 calories/day, and adult men need 2,000–3,000 calories/day. Use our Calorie Calculator to find your specific number.

A calorie deficit occurs when you consume fewer calories than your body burns in a day. This forces your body to use stored energy (fat) for fuel, resulting in weight loss. A deficit of 500 calories per day typically leads to 1 lb of weight loss per week.

Technically, yes, from a pure energy standpoint (100 calories of candy = 100 calories of broccoli). However, biologically, they affect hormones, hunger, and metabolism differently. Protein requires more energy to digest than fats, and fiber-rich foods keep you full longer than sugar.

Empty calories come from solid fats and added sugars in foods that offer little to no nutritional value (vitamins, minerals, fiber). Examples include soda, alcohol, candy, and pastries.

No, but it is the most precise method. You can also lose weight by controlling portions, intermittent fasting, or focusing on low-calorie-density foods (like vegetables), which naturally limits intake without strict counting.

Not directly. Calories are calories, regardless of the time. However, late-night eating often leads to mindless snacking on high-calorie foods, pushing you into a surplus. It's the 'what' and 'how much', not the 'when'.

TEF is the energy your body uses to digest, absorb, and store nutrients. Protein has the highest TEF (20-30% of its calories are burned just digesting it), compared to curbs (5-10%) and fats (0-3%).

True starvation mode (where your body shuts down to survive) is rare and happens only in extreme malnutrition. However, 'metabolic adaptation' is real: as you lose weight, your body becomes more efficient and burns fewer calories, which can slow down weight loss.

Muscle is more metabolically active than fat. One pound of muscle burns about 6-7 calories per day at rest, whereas one pound of fat burns about 2 calories per day. Building muscle raises your BMR.

Generally, no or only partially. Fitness trackers often overestimate calories burned by 20-30%. If your goal is weight loss, treat exercise calories as a 'bonus' deficit rather than eating them all back.

You may have hit a plateau. This can happen because your metabolic rate has dropped match your new lower weight, or you are retaining water from stress/cortisol, or 'hidden' calories have crept back in. Taking a diet break at maintenance calories can helps reset hormones.