How Many Calories Should You be Eating?

 

How many calories should you be eating? If your goal is fat loss, muscle gain, or maintaining your current physique, calories are the foundation. Not because calories are the only thing that matters, but because they set the limits for everything else you do with nutrition.

The more important question is how many calories you should be eating to actually move toward your goal without guessing or constantly restarting.

The most effective approach is to start with a solid estimate based on your body and activity level, stay consistent for a few weeks, and then adjust based on how your body responds.

This guide will walk you through how to estimate your daily calorie intake and how to adjust it for fat loss or muscle gain. If you want to take things a step further and dial in body composition, check out my guide on calculating your macros.

The Science Behind a Calorie

A calorie is simply a unit used to measure energy.

In scientific terms, a “small calorie” represents the amount of energy required to raise the temperature of 1 gram of water by 1°C.

In nutrition, we use “Calories” (capital C), also known as kilocalories (kcal). One food Calorie equals 1,000 small calories.

When you eat food, your body breaks it down and releases energy. Some of that energy is used immediately, while the rest can be stored for later use.

This is why calories matter. They represent your energy budget. If your goal is fat loss or muscle gain, controlling that budget is essential.

Calculating the Amount of Calories You Should Eat

There are several methods to estimate how many calories you need to maintain your current body weight. All of them are influenced by factors such as:

• Body weight
• Body fat percentage
• Activity level
• Age
• Diet history

Your calorie needs are individual and will change over time. The goal isn’t perfection — it’s finding a reasonable starting point and adjusting as needed.

Estimate Caloric Needs

1. Quick estimate: Multiply your bodyweight (in pounds) by 14–16. Use the lower end if you are less active and the higher end if you are more active.
2. Harris-Benedict Equation:
   • Men: 66 + (13.7 × weight in kg) + (5 × height in cm) − (6.8 × age)
   • Women: 655 + (9.6 × weight in kg) + (1.7 × height in cm) − (4.7 × age)
3. Mifflin-St Jeor (recommended):
   • Men: (10 × weight in kg) + (6.25 × height in cm) − (5 × age) + 5
   • Women: (10 × weight in kg) + (6.25 × height in cm) − (5 × age) − 161
   • Multiply by activity level:
     • Sedentary: 1.2
     • Light activity: 1.375
     • Moderate activity: 1.55
     • Active: 1.725
     • Very active: 1.9
4. Use an online calculator for a quick and simple estimate.

TDEE Calculator

The calculator below estimates your Total Daily Energy Expenditure (TDEE), which is the number of calories needed to maintain your current body weight.

Calculate for Fat Loss

Once you know your TDEE, the next step is to create a calorie deficit. A deficit means eating fewer calories than your body needs to maintain its current weight.

A good starting point for most people is a 20–25% reduction from maintenance. This range is aggressive enough to produce results while still being sustainable for most individuals.

For example, if your TDEE is 2,500 calories, a 20% deficit puts you at 2,000 calories per day, while a 25% deficit puts you at 1,875 calories per day.

Calculate for Muscle Gain

When the goal is to gain muscle, most people want to do so without gaining unnecessary fat. Research suggests a surplus of about 10–20% for novice to intermediate lifters.

For most recreational lifters, a smaller surplus of 5–10% above maintenance is easier to manage. This often works out to roughly 16–18 calories per pound of bodyweight.

Beginners are a special case. During the first year of resistance training, it’s common to gain muscle even while in a calorie deficit due to rapid adaptations.

Best Way to Count Calories

To change your body weight intentionally, you need a clear calorie target. Tracking calories isn’t about restriction — it’s about awareness.

Eating purely based on hunger can work for maintenance, but it becomes unreliable for fat loss or muscle gain because hunger doesn’t always reflect calorie intake.

Using a tracking app can be helpful for staying accountable and checking whether you have room for additional food while still hitting your target.

Legacy Strength Approach

I use a combination of meal planning and a calorie-tracking app. Once calorie and macro targets are set, I build meals around foods I actually enjoy, then log them to keep everything honest.

Planning ahead removes most of the stress. The app becomes a tool for confirmation rather than something you rely on every single decision.

The goal is sustainability — not suffering.

Conclusion

Fat loss and muscle gain don’t have to be complicated, but they do require structure. Training harder can’t make up for poor nutrition. Your diet sets the ceiling for your results.

1. Estimate your TDEE
2. Adjust calories based on your goal
3. Plan meals around your target
4. Track intake if it helps you stay consistent

Pair this with a solid resistance training program and adequate recovery, and you’ll be ahead of most people.

References

1. Osilla EV, Safadi AO, Sharma S. Calories. StatPearls. https://www.ncbi.nlm.nih.gov/books/NBK499909/
2. Woźniak J et al. Food Science & Nutrition, 2024. https://doi.org/10.1002/fsn3.4442
3. Iraki J et al. Sports (Basel). 2019;7(7):154.