How Many Calories Should I Eat to Lose Weight?
Every diet should start with the basic question:
how many calories should I eat to lose weight?
There are five different ways to get an answer and find out how many
calories you need. The best method for you depends on your goals, how
much money you want to spend, and your access to various health
services.
Look at these five different methods for determining your caloric needs and evaluate the pros and cons for yourself.
Keep a Pre-Diet Food Journal
A pre-diet food journal is the perfect starting point for evaluating your caloric needs. Before you start a weight loss program,
take one week to evaluate your current caloric intake. Don't make any
changes to your diet, just write down everything you eat and the number
of calories in each food. You should do this at a time when your weight
is stable and your daily activity is typical.
After a week of recording your food intake, add the total number of
calories for each day and divide by seven to get an average daily
caloric intake. This should provide a general guideline for the number
of calories your body needs to maintain its current weight. To lose
weight, you need to decrease that number by roughly 500-600 calories per
day.
- Pros: Inexpensive, reinforces good weight loss habits such as food journaling.
- Cons: Requires tedious recording and may not be accurate if you aren't specific about measuring and recording your food portions.
Use an Online Calorie Calculator
There are several easy-to-use online caloric needs calculators, like the one at CalorieCount.com.
These tools provide a quick and easy estimate of the number of calories
you need to eat to lose weight. To get the most accurate number, you
need to know your current weight, height and goal weight. You also need
to assess your daily activity level.
The number generated from these calculators is usually based on the Harris-Benedict formula
for determining basal metabolic rate (BMR). The formula is widely
recognized by experts as a reasonable estimate for daily caloric need.
However, it is only as accurate as the information you provide and the
answer is based on general guidelines. Daily activity level, for
example, varies widely from person to person and there is no way for a
single formula to accurately predict the metabolic impact of your specific activity level.
- Pros: Provides a fast answer, free to use
- Cons: Only based on general guidelines and estimates
Perform Metabolic Testing

Many gyms and other health centers now provide metabolic testing for a
fee. Metabolic testing measures the number of calories that your body
burns at rest (RMR) and the number of fat and carbohydrate calories your
body burns while exercising at various exercise intensities.
As part of your metabolic assessment, many trainers will also provide a
metabolic training plan that will help you to burn more fat calories
during exercise so that you lose weight more effectively.
While this seems like the most accurate way to find out how many
calories you need, there has been some criticism of this testing
process. The accuracy of your test may depend on the quality of
equipment used, how often it is calibrated and the skill level of the
person doing the testing. The service can be expensive and may require a
gym membership.
- Pros: Results are personalized and based on your specific performance.
- Cons: Expensive and not widely available and some say that results are not as accurate as advertised.
Wear an Activity Monitor

Activity monitors, like the BodyMedia FIT band
and BodyBugg are essentially high-tech food and activity journals. They
provide a wide variety of data on your smartphone or computer.
BodyMedia FIT , for example, measures steps per day, vigorous activity,
and moderate activity. When you log your meals, it also calculates your
intake of calories, fat grams, carbohydrate grams and protein. To set up
the plan, the program estimates the number of calories you need.
The tracking device is worn on your arm so that it can measure your
movement, body temperature and skin response. In order to use the
devices with your computer you also need to purchase a subscription to
their online service.
- Pros: Convenient, easy to use and measures a number of different variables
- Cons: Devices can be expensive ($100-200) and require an ongoing subscription after the initial subscription expires
Meet with a Registered Dietitian

A registered dietitian will work with you to determine the number of
calories you need to eat to lose weight, and the proportion of
carbohydrates, protein and fat. A good dietitian will also strategize
with you to overcome typical barriers that have prevented you from losing weight in the past.
Many physicians can provide referrals to a registered dietitian. In
some cases, the service may be covered by insurance if you have health
conditions that are affected by your weight. But every insurance plan
is different, so check with your provider to get details.
- Pros: Personalized, professional, face-to-face approach.
- Cons: May be costly or inconvenient if not covered by insurance
The Bottom Line: What's Best for Me?

If price and convenience are important factors for you, there is no
reason not to start with the cheapest and easiest way to calculate your
caloric needs. Keep a pre-diet food journal and compare your result to
the number you get when you use a free online calculator. You’ll get a
good estimate of the number of calories you need to eat to lose weight.
Keep in mind though, that the success of your food journal, your calorie counting and ultimately of your ability to lose weight depends entirely on the accuracy of your recording. Make sure you measure specific serving sizes and accurately count calories.
If you record data properly, cut calories and still don't see the
results you want, consider investing more money into one of the other
methods. A registered dietitian or metabolic testing are good options
for people who prefer face-to-face support and accountability.