How many calories should I eat to lose weight?  How many calories does it take to lose one pound?  What number of calories should I eat in a day? While these questions may seem like they’re on the right track, there’s a catch that makes finding the answer a bit less simple than discerning just one number.  The key to losing weight is, in fact, a ratio – the number of calories you need compared to the number of calories you take in. It’s often referred to in terms of a caloric deficit or a caloric surplus, and is what dictates whether or you gain or lose weight.  There can be exceptions in very unique circumstances, but as a general rule, caloric deficit versus surplus is what you need to pay attention to if your goal is to shed pounds. 

What exactly is a caloric deficit versus surplus, and what does it mean?

A caloric surplus means that you consume more calories than you burn.  In other words, you have more calories than you need to function, which is the condition under which you gain weight.  Since your body has more units of energy (calories) than it requires, it stores the extra calories as fat. A caloric deficit, on the other hand, is the exact opposite of a surplus, with the opposite effect – which is what you want if your goal is to lose weight.  When you have a deficit you expend more calories than you consume, and your body has to tap into fat reserves to get the extra energy it needs.  

How do I know how many calories I need?

The optimum number of calories required for each person varies.  So how can you find out how many you need?  Luckily, there are a couple tools to help you find out your specific basal metabolic rate, or BMR.  Created by physicians, you can use the formulas of either Dr. Anna Z. Feldman – an endocrinologist at Joslin Diabetes Center – or what’s called the Mifflin St. Jeor equation.  Both use similar methods that work equally well.  The BMR, however, will only tell you how many calories you need for basic function – like keeping your heart beating and your lungs breathing – and doesn’t factor in daily activity such as walking or other exercise.  In order to arrive at the number of calories you need for a normal day, including all your activities, the U.S. Department of Agriculture has you covered with their interactive calculator that lets you input your BMR in addition to selecting your activity level.  This tool will give you a better number to reference when considering how many calories you need to be taking in.

I know how many calories I need; how do I create a deficit?

The key to creating a caloric deficit is to expend more energy than you absorb.  This means you can create a caloric deficit in one of two ways. You can either cut back on what you intake by reducing the amount of calories you consume or increase the amount of energy you expend through exercise or other activity.  Both methods, as well as a combination of the two, will work to create a deficit. It’s estimated that, in order to lose roughly a pound per week, that calorie expenditure should exceed intake by 500 calories a day (or 3,500 calories a week).  So depending on the method you’ve chosen for reducing your deficit, you can either subtract the calories by altering either the quantity or quality of food you eat (as well as what you drink), or use the Calorie Control Council’s handy exercise calculator to determine how many calories you’ll burn based on what types of exercise you add.  

A Few Things to Keep In Mind

Keep it healthy.

A healthy rate of weight loss is one to two pounds per week, according to Jim White of the Academy of Nutrition and Dietetics.  Additionally, you don’t want to drop under 1,200 calories per day.  Letting your energy intake fall too low can make your body react negatively, attempting to store fat in the belief that you’re starving and accomplishing the opposite of what you’re trying to do.  Worse, under 1,200 calories a day is below the threshold of most people’s basal metabolic rate, depriving your body of the nutrition it needs to function properly.  

It matters what you eat.

When you’re trying to lose weight, and especially when you’re intaking fewer calories than normal, it matters what type of calories you eat.  You want to make sure you give your body the building blocks it needs to maintain healthy organs and systems, and not wasting calories on low-quality foods that don’t provide good nutrition.  Whole foods have a tendency to fill you up faster as well.  If that weren’t enough, the fiber and other benefits from eating healthy foods can help support a more efficient digestive system in addition to your overall health, helping you maintain a healthy weight more naturally.  

Don’t be afraid to build muscle.

Sometimes the best method of running a caloric deficit is to combine exercise and cutting calories.  In addition to being part of a healthy lifestyle that comes with a host of other benefits, exercise builds muscle, which is metabolically active.  This means that, even when you’re resting, muscles burn more calories than fat.  It’s also been noted that exercise, especially any type of strength training, boosts your metabolism afterward.  This can help you lose weight faster, in addition to getting stronger.

There are a lot of products out there that promise to boost metabolism, magically shed pounds, or create other amazing results by way of some new formula.  The reality, however, is that the secret to losing weight is actually just math followed by lifestyle decisions that make the numbers add up the way you want them to.  So before you ask, “How many calories should I eat to lose a pound?,” first find out how many you consume. Paying attention to whether you have a caloric deficit or surplus, as well as understanding how many calories you need, can help you determine the best and healthiest way to reach your weight loss goals – no purchase required.