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How Many Calories Should I Eat to Lose Weight?

How Many Calories Should I Eat to Lose WeightHave you been wondering, how many calories should I eat to lose weight? Read on to learn a quick and simple way to figure that out (as well as the complex method for those of you who are interested), and important things to keep in mind when calorie counting.

Calorie Counting – Total Flexibility, But At a Price

Calorie counting can be a great diet if you don’t want to be limited as to what you can eat. On this diet there is no food that you cannot eat.

But just like with your monthly money budget, there is only so much money. If you indulge in something expensive, you will have to balance it with something cheaper in order to stay within your budget.

On the calorie counting diet, you can eat what you want, but if you don’t want to be hungry, every indulgence comes at a price. Yes, you can have that slice of chocolate cake (high calorie), but that probably means cabbage soup (low calories) for dinner to fill you up.

Burn More Than You Consume

The amount of calories you can eat to lose weight will depend on the amount of calories you burn every day, through just living, and various activities. You will need to eat less calories than you burn, to lose weight. Or put the other day, you have to burn more calories than you consume!

how many calories should i eat to lose weight scale

You will be… If….
Losing weight …you are eating fewer calories than you are using. Your body will pull from its fat storage cells for energy, so your weight will decrease.
Maintaining your weight …you are eating roughly the same number of calories that your body is using. Your weight will remain stable.
Gaining weight …you are eating more calories than your body is using. You will store these extra calories as fat and you’ll gain weight.

Here is a quick video (1 min) with some tips on good habits for keeping track of your calories:

 

How Many Calories Should I Eat to Lose Weight? The Quick and Easy Way to Calculate

There is complete science behind this with competing formulas and theories, and all of that is provided below, but basically it can be boiled down to 2 simple steps.

Step 1:

Determine how many calories your body burns to maintain your current weight. In other words, how many calories can you eat today without gaining or losing weight? This is also referred to as your Active Metabolic Rate (AMR). Here is a simple way to determine your AMR based on your activity level.

  • Exercise 0 to 2 times a week: Body Weight in pounds x 13
  • Exercise 3 to 4 times a week: Body Weight in pounds x 15
  • Exercise 5 to 7 times a week: Body Weight in pounds x 17

Step 2:

Decide on a weight loss goal. The recommended (Harvard Medical School) weekly weight loss is 1 to 2 pounds. That may sound slow, but there are good reasons for it, and those are explained below. In order to lose 1 pound a week, you will need to eat about 500 calories less per day than your body burns to maintain its weight (your AMR, see step1).
Here is how many calories you should eat per day depending on your weight loss goal:
Weekly Weight Loss Goal of 1 pound: Your AMR minus 500 calories
Weekly Weight Loss Goal of 2 pounds: Your AMR minus 1,000 calories

For Example:
Let’s run an example to show how simple this quick and easy approach is to calculate how many calories you should eat to lose weight. Say your current weight is 150 pounds, you exercise 3 times a week, and you would like to lose 1 pound a week.

Step 1 – Calculate your AMR: 150 pounds x 15 = 2,250 calories. This is how many calories your body burns on a daily basis, given your activity level. If you were to eat 2,250 calories per day you would neither gain nor lose weight.
Step 2 – Calculate how many calories you should eat to lose weight: In this example, you decided to lose 1 pound a week. Thus you need to deduct 500 calories from your daily AMR of 2,250 calories, which results in 1,750 calories (2,250 AMR calories minus 500 calories = 1,750 calories). If you eat 1,750 calories per day, you should lose about 1 pound per week.

How Many Calories to Lose Weight Calculator

Calculator: Below is a calculator to calculate how many calories you should eat to lose weight based on the above quick and easy way. Calculate and see the answer to your question, how many calories should I eat to lose weight?

  • Calories per day to maintain current weight (AMR): {{AMR}}
  • Daily calories to reach your weekly weight loss goal: {{daily_calories}}
The above quick and easy calculation should give you a good idea on how many calories you can eat to lose weight. If you want to get a more detailed AMR calculation (that factors in age and gender), and learn about what to watch out for while you are on a calorie based diet (starvation mode, weight loss plateau, ideal calorie deficit for weight loss, exercise for weight loss) keep on reading!

How Many Calories Should I Eat to Lose Weight? The more precise way to calculate how many calories you should eat to lose weight

As indicated above there is a whole science around BMR/AMR calculations, and it can get really complicated. If that interests you, keep on reading, otherwise you can skip to the next topic further down to read the helpful tips and potential pitfalls of a calorie based diet (starvation mode, weight loss plateau, ideal calorie deficit for weight loss, exercise for weight loss).

Active Metabolic Rate (AMR), Basal Metabolic Rate (BMR), Resting Metabolic Rate (RMR), and Resting Energy Expenditure (REE)

There are various terms flying around to describe how many calories you are burning just by being alive and by factoring in your activity level.

  • Active Metabolic Rate (AMR): The most important measure for you. Your AMR is your BMR plus the calories you need to support your activities throughout the day like walking, jogging, reading, or cooking.
  • Basal Metabolic Rate (BMR): The amount of calories a person will burn if he/she is at rest for 24 hours. It is the amount of calories needed to keep the body functioning, the heart beating, the lungs breathing and the body temperature normal.
    • Resting Metabolic Rate (RMR): The RMR is essentially the same as the BMR. The only difference is on how the RMR is measured. For measurement purposes, for example, the BMR requires 12 hours of fasting prior to measurement, whereas the RMR does not require fasting. There are a couple more minor differences but that is more important for the scientific community.
    • Resting Energy Expenditure (REE): The REE is essentially the same as the BMR. The only difference is how the REE is measured. REE is not quite as accurate, but generally comes up with a value that is pretty close to BMR, does not require fasting, and only takes a few hours in the lab. Again, the difference is mainly important for the scientific community.

To recap, the Resting Energy Expenditure (REE) and the Resting Metabolic Rate (RMR) are essentially the same as the Basal Metabolic Rate (BMR). The differences among the 3 (REE, RMR, and BMR) are mainly important to the scientific community. For most non-scientific people, the Active Metabolic Rate (AMR) and the Basal Metabolic Rate (BMR) are the 2 concepts to focus on.

AMR & BMR Formulas

A more precise and the most often used AMR and BMR formula is the Harris-Benedict Equation. It is one of the oldest formulas around, and came from a study by James Harris and Francis Benedict and was published in 1918 by the Carnegie Institution of Washington under the title “A Biometric Study of Human Basal Metabolism.”

This BMR differs for women and men, and takes into consideration your current weight, your height, and your age.

Women BMR = 655 + (4.35 x weight in pounds) + (4.7 x height in inches) – (4.7 x age in years)
Men BMR = 66 + (6.23 x weight in pounds) + (12.7 x height in inches) – (6.8 x age in years)

You need then to calculate your active metabolic rate (AMR) by starting with your basal metabolic rate (BMR) and adjusting it by estimating your current level of activity. If you are:

  • Sedentary (little or no exercise): your AMR = BMR x 1.2
  • Lightly active (light exercise/work 1-3 days per week): your AMR = BMR x 1.375
  • Moderately active (moderate exercise/work 3-5 days per week): your AMR = BMR x 1.55
  • Very active (hard exercise/work 6-7 days a week): your AMR = BMR x 1.725
  • Extra active (very hard exercise/work 6-7 days a week): your AMR = BMR x 1.9

There are other AMR/BMR formulas out there, with the most famous one being the Revised Harris-Benedict Equation, the Mifflin St Jeor Equation, the Katch-McArdle Formula, and the Cunningham Formula.

However, the original Harris-Benedict Equation is still the most commonly used BMR equation.

AMR/BMR Calculator based on the Harris – Benedict Equation

  • Calories per day needed to maintain essential living functions such as breathing and digestion (BMR): {{BMR}}
  • Calories per day to maintain current weight (AMR): {{AMR}}
  • Daily calories to reach your weekly weight loss goal: {{daily_calories}}

Potential Pitfalls of a Calorie Based Diet – Tricks to Be Successful When You Are Counting Calories

Starvation Mode

You may think, hey I am really eager to lose weight. If I reduce my daily calorie intake by 500 calories and that reduces my weight by 1 pound a week, why don’t I reduce it by 2,000 calories and lose 4 pounds a week? If you can stand the hunger that would be nice, wouldn’t it? Unfortunately, doing that actually only makes it so much harder for you to lose weight.

Here is a good video explaining how that works. Dr. David Edelson explains the starvation mode, and  the impact of the starvation mode in this short video (2 min):


As described in the video, if you eat too little, your body thinks it is starving, and  it will reduce the amount of daily calories it burns. So, you will have made it so much harder for your body to lose weight. By eating too little, not only will you be probably suffering from hunger, but to make it worse, your body will reduce the amount of daily calories it burns.

If you now stop dieting because it doesn’t work, or doesn’t work well, you will gain weight quickly since your body is still burning less calories than it used to prior to the diet. Your body will eventually adjust and burn the same calories you used to burn prior to your diet, but only after you’ve gained your weight back, and then some!

The recommended minimum calories to avoid starvation mode differ by gender and are:

  • For women, 1,200 calories per day
  • For men, 1,500 calories per day

Again if you eat less than the above minimum, your body will think that it is starving, and will try to conserve energy. It will lower your metabolism (BMR), and reduce the daily calories it burns. This will result in slower weight loss.

There is also a health aspect to keep in mind. If you eat less than the above recommended calories (1,200 for women, and 1,500 for men) it will be extremely difficult to eat a balanced diet and obtain all the nutrients that your body needs to stay healthy.

The Weight Loss Plateau

You started to diet, you lost some weight, everything was going fine, and all of a sudden your scale stops moving. That can be a very frustrating experience, but it is also completely normal. Almost everyone on a diet will reach a weight loss plateau at some point. In other words, no need to get frustrated, no need to give up. This is a normal obstacle for people on their weight loss journey.

Having said that, what can you do if you hit a weight loss plateau?

According to Kelly Brownell, Ph.D., Yale School of Medicine, the best advice is to keep on doing what you’ve been doing before.

Losing weight can at times be a stair step process; nothing happens for a while until all of a sudden the weight drops. And if the diet worked for you in the past, staying the course and powering through the plateau is probably the best advice.

At the same time, there are a few things you can do to check that you are doing everything right:

1. Funny Math

Are you still counting all your food, and counting it correctly? Do you count the calories when you taste food while cooking? How about the calories in dressings and condiments? It is easy to underestimate the food we eat, and overestimate calories burned. You are probably counting everything correctly, but just in case, you want to be extra vigilant here to make sure that you are not sabotaging yourself.

2. Not eating enough

If you don’t eat enough (less than 1,200 calories for women and less than 1,500 calories for men), your body enters starvation mode (see article above). Your body thinks it is starving and will reduce the amount of calories it burns. You will need to increase your calorie intake above those minimum intakes.

3. Weight Loss

If you remember the BMR and AMR calculation from above, as you weigh less, your body will need less calories. If you lost a lot of weight (great for you!) the calories your body burns has also gone down. If that is the case for you, you will need to adjust down your calorie intake. You can do that by calculating how many calories you should eat based on your current (lighter) weight.

On the other hand, a weight loss plateau is also a great opportunity to decide if further weight loss is worth all the work. You may already be at a perfectly healthy weight. If that is the case, start to focus now on maintaining what you have achieved. If you are still above your desired weight, hang in there and don’t let the weight loss plateau derail you.

Unsustainable Calorie Deficit for Weight Loss

To lose one pound a week, you need to create a calorie deficit of 3,500 calories during the week. Since a week has seven days, to get the daily calorie deficit, you divide 3,500 calories by seven and get 500. However, many people take that to an extreme, and try to run a bigger calorie deficit. The problem is that is not sustainable. At some point your willpower is going to cave if the calorie deficit is too large. Also, if your calorie deficit is too large, your body goes into starvation mode (see article above) and burns less calories. Not exactly what you want.

What does work is a sustainable and sensible calorie deficit, combined with regular exercise. According to Harvard Medical School, the recommended daily calorie deficit is between 500 (1 pound of weight loss a week) and 1,000 calories (2 pounds of weight loss a week).

That may seem too slow, but if you can sustain a deficit for 10 weeks (a little more than 2 months), you can lose between 10 and 20 pounds. That would be quite an accomplishment. Also keeping the deficit between 500 to 1000 calories per day leaves you room for occasional treats and/or dining out, which makes it so much easier to continue the diet and lose even more weight.

Exercise Alone for Weight Loss

Exercise alone for weight loss is in most cases not easy. You would need to go jogging for 2 hours at 5 mph to burn about 1,000 calories. Unless you love exercise and have extra 2 hours a day to kill, it would be much easier to create a daily calorie deficit of 1,000 calories through eating less.

Where exercise helps though, is on 2 fronts.

  • Muscles burn more calories than fat – If you do muscle exercise you ensure that you don’t lose muscle weight during your diet. People who are muscular typically have a higher BMR (basal metabolic rate), which results in their body burning more calories even when resting.
  • It makes your body more sensitive to insulin, which means it needs less insulin to reduce your blood sugar. This is a big topic, but in nutshell by exercising you reduce the amount of insulin in your system which helps with the weight loss.  According to Duke University, aerobic exercise (walking, jogging, swimming, etc.) is the best way to improve insulin sensitivity.

In a nutshell, to get the best benefit from exercising for weight loss, you should do some combination of aerobic exercise (walking, jogging, swimming, etc.) with some amount of weight exercise to protect and/or build your muscles.