How to Lose Body Fat Safely

Discover how to calculate your calories to change your body composition without sacrificing your health in the process.

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You don’t have to crash diet to lose fat. Period. There are ways to achieve your fat-loss goals without sacrificing your health, hormones and state of being.

Let’s start with the basics. In order to burn fat, there must be a deficit between caloric intake and caloric expenditure. This can be implemented slowly or quickly, depending on your goal and how much body fat you hope to lose. 

There are two ways to create a deficit: exercise and diet. You also can combine them. For example, if you need to create a 500-calorie daily deficit, you can potentially cut 500 calories from your meals or burn 500 calories from exercise or combine the two, in which case you may cut 250 calories worth of food and increase your exercise output by 250 calories.

Important note: You don’t necessarily need to create a calorie deficit through concentrated exercise. You can simply increase your daily activity and burn calories during the course of your day-to-day life. This is called non-exercise activity thermogenesis. By increasing your activity throughout the day, every day, you may end up burning more calories compared to hitting the gym for an extra hour. 

Is it better to create a fat-loss deficit through diet or exercise?

There are a few factors to consider.

In the case of a woman with a normal menstrual cycle, studies show that increasing exercise compared to decreasing calorie intake has less of a negative effect on leptin levels and hormonal signals. Hunger signals are stronger when there’s a calorie deficit. However, when exercise causes the deficit, those hunger signals are generally not flaring — provided the deficit created from exercise isn’t excessive. 

When it comes to exercise, you also have to consider how the deficit is created. 

To accomplish a calorie deficit from training, doing weightlifting and/or strength training at moderate intensity five to seven times per week is one of the best approaches. First, because it may be too intense to train for 100 percent of the deficit in one session. Second, because it helps maintain lean body mass (muscle) without overstressing the body. Remember, we want to maintain muscle mass. 

Aerobic exercise also can create a deficit, but aerobic exercise doesn’t help with lean body mass.

Studies show that the most effective way to create a deficit is through a combination of both exercise (weightlifting specifically) and diet. One study in particular, published in the International Journal of Sport Nutrition and Exercise Metabolism, found that resistance training and diet showed more fat lost and lean body mass gained than with aerobic exercise combined with a caloric deficit.

Fruits and vegetables on a cutting board.
Don’t just choose a number of calories and cut. Put in some forethought or work with a professional.

How many calories should you cut back to lose fat?

The number of calories you should decrease in order to create a deficit varies from person to person.

It’s crucial to avoid dropping below a critical energy balance, which could place you in a suboptimal hormonal or metabolic state. So don’t just choose a number (i.e., 500 calories) and cut. Put in some forethought or work with a professional to determine what’s right for you.

Different women eat different amounts. For example, if one woman eats 3,000 calories per day and another woman eats 2,200 calories a day, cutting 500 calories would impact them differently. For the first woman, a 500-calorie deficit would cause her little to no stress. A person can still function on 2,500 calories a day. On the other hand, the second woman would be down to 1,700 calories, which may be below her critical threshold and could cause adverse health effects (for reference, critical threshold is 13.6 cal/lb lean body mass).

In creating a deficit, you need to assess the percentage of calories you plan to remove from your diet and also take into account your current body fat to ensure you remain within a healthy energy range. 

Remember: A slow fat-loss journey (especially for smaller women) is ideal.

A healthy deficit would land about 20 percent of a person’s maintenance calories. This means that a woman with a higher caloric intake would have a greater number of calories to remove, while a woman with a lower caloric intake would have a smaller reduction. Note: Dropping lower than 30 percent of maintenance calories may put you at risk of dropping below your critical energy availability threshold and experiencing subsequent hormonal issues.

What’s a healthy rate of weight loss?

In general, a healthy weight-loss goal is 1 to 2 pounds per week at most. A smaller woman should shoot for 0.5 to 1 pound per week, while a larger women would be safe shooting for 1.5 to 2 pounds per week. 

Another potential way to look at weight loss is by percentage of bodyweight. If your goal is to lose 10 percent of your bodyweight, you can break that down to 1 percent per week over 10 weeks. A healthy and safe rate for lean women is 0.5 percent per week, average women can lose about 1 percent per week and obese women can safely lose 1 to 1.5 percent of bodyweight per week.

The key is a slow and steady weight loss. The road may be slower than you expected or hoped, but realistic expectations are crucial in achieving sustainable weight and/or fat loss.

Do the right thing the first time around, don’t cut corners and set yourself up for long-term success.