When it comes to weight loss, many people use the terms “burning calories” and “burning fat” interchangeably. But are they really the same thing? The short answer is no, burning calories and burning fat are related but distinct processes.
What does it mean to burn calories?
Burning calories refers to the number of calories your body uses for energy. Your body requires calories to function and be physically active. The number of calories you burn in a day is known as your Total Daily Energy Expenditure (TDEE). This is made up of:
- Basal Metabolic Rate (BMR) – The calories used to keep your body functioning at rest, including breathing and other automatic processes.
- Physical Activity – The calories used when you are active, like walking, exercising, fidgeting, etc.
- Thermic Effect of Food (TEF) – The calories burned through digesting, absorbing and metabolizing the food you eat.
To lose weight, you need to burn more calories than you consume. A calorie deficit forces your body to use stored energy sources, like fat, to make up the difference. So burning more calories through exercise or eating less food can contribute to fat loss over time.
What does it mean to burn fat?
Burning fat specifically refers to the release of stored body fat for energy. Your body stores excess calories as triglycerides in fat cells throughout the body. When your body needs energy and you are in a calorie deficit, it releases these stored triglycerides and breaks them down into glycerol and free fatty acids. The fatty acids then enter the bloodstream and are transported to tissues to be used for energy.
So burning fat requires your body to first break down triglycerides and mobilize the released fat. This is a complex biochemical process regulated by hormones, enzymes, and other factors. The act of burning fat itself takes place in organs and tissues, not directly in fat cells.
How are burning calories and fat connected?
While they are distinct processes, burning calories and fat are very connected. Some key points about how they interact:
- You must be in a calorie deficit to burn fat – If you are eating enough calories to maintain your weight, your body can get all the energy it needs from food, and it has no need to burn stored fat.
- Burning calories from any source can contribute to fat loss over time – The calories used for energy can come from carbs, protein, fat, or existing fat stores. But to tap into fat stores, a deficit is required.
- Burning fat directly contributes to burning more calories – Since stored fat provides 9 calories per gram, burning 100 grams of fat would burn 900 calories.
- The body preferentially burns calories from carbs and fat – Protein is generally spared unless calories are very restricted for an extended time.
- Cardio exercise speeds up fat burning – Aerobic activities like running and cycling require many calories and tap into fat stores more readily.
In summary, a calorie deficit forces your body to burn fat stores to make up the difference in energy. So creating a deficit through diet, exercise, or both is the key that unlocks stored fat and enables fat loss.
What factors influence fat burning?
Several key factors play a role in influencing how and at what rate your body can burn fat:
- Calorie balance – As above, a calorie deficit is required for fat loss. The greater the deficit, the faster fat can be burned, although very low calorie intakes are not recommended.
- Meal frequency – Eating smaller meals more often can help keep metabolism and energy levels higher versus fewer larger meals.
- Nutrient intake – Getting adequate protein intake helps retain calorie-burning muscle while in a deficit. Carbs fuel activity; very low carbs may hinder athletic performance.
- Exercise – Higher intensity exercise like HIIT training forces the body to burn more calories and tap into fat stores. Strength training builds metabolism-boosting muscle.
- Sleep – Getting enough quality sleep allows fat burning hormones to work optimally for energy balance.
- Stress management – Chronic stress raises cortisol, which can interfere with fat burning.
- Hydration – Being dehydrated inhibits fat metabolism and energy levels for activity.
Optimizing as many factors as possible creates the ideal environment for your body to efficiently access and burn fat stores.
Does burning fat lead to weight loss?
Yes, burning fat can directly contribute to weight loss. Each pound of fat contains about 3,500 calories. So to lose one pound of fat, your body has to create a 3,500 calorie deficit through diet, exercise, or a combination of both. Burning an extra 500-1000 calories from fat stores per day can lead to a 1-2 pound weight loss per week.
However, whether or not the pounds lost come specifically from fat stores also depends on other factors:
- If you maintain muscle through strength training, any weight loss is more likely to come from fat rather than muscle.
- The rate of fat loss varies based on genetics, age, activity levels, and metabolic factors that determine how readily your body taps into fat.
- Initially, weight loss may come from fluid loss before fat stores are tapped. Burning actual fat takes longer.
- A very low calorie intake can sometimes cause temporary water retention that masks fat loss on the scale.
So while burning fat definitely leads to weight loss over time, the time course and amount of fat loss varies individually. Patience and persistence are key.
Should you target burning fat or calories?
For the reasons above, it’s clear that supporting both fat burning and calorie burning is important for weight loss. However, focusing more on creating a calorie deficit will ultimately drive fat loss.
Targeting “fat burning” on its own can be misguided. No pill or supplement will magically just burn fat while you maintain a calorie surplus from eating too much. Creating a deficit through fewer calories in and more calories out is the only way to reliably tap into stored fat over time.
Once in a deficit, it is helpful to use diet and exercise strategies that optimize fat burning hormones and enzymes. But the deficit remains the master switch to unlock fat loss.
How to put fat and calorie burning into practice
Here are some evidence-based steps you can take to create a calorie deficit to lose fat:
- Use a TDEE calculator to estimate your maintenance calories, then aim for a modest daily deficit of 500 calories.
- Track your calorie intake for a while to get an accurate assessment of how much you’re eating.
- Focus your diet on whole, minimally processed lean proteins, fruits, veggies, and whole grains for nutrition and satiety.
- Incorporate strength training to retain calorie-burning muscle mass when losing weight.
- Do 150-300 minutes of moderate cardio exercise per week, like brisk walking or swimming.
- Consider HIIT workouts 1-3 times a week to maximally tap into fat stores with intense exercise.
- Get enough sleep and control stress to optimize your hormones and metabolism.
By taking a holistic approach you can reach a modest calorie deficit through both diet and exercise while supporting your body’s innate fat burning potential.
The bottom line
Burning fat and burning calories are distinct but closely interrelated processes. While targeting “fat burning” alone won’t lead to weight loss, creating a calorie deficit through diet, exercise, or both will force your body to tap into fat stores as an energy source, leading to fat loss over time. A sustainable, moderate calorie deficit combined with training, nutrition, sleep, and stress management strategies will maximize fat burning potential and help you reach your body composition goals.