Weight Loss: How Many Calories Should You Eat Based On Your Basal Metabolic Rate

Key Points

  • You are not going to lose weight purely from fat tissue
  • Slashing calories or over- exercising doesn’t work (in the long term)
  • High Protein Diet= ⇧ Basal Metabolic Rate ⇧ Fat Loss
  • Weight Training= ⇧ Basal Metabolic Rate ⇧ Fat Loss


Lose 1 Pound of Fat Per Week

We have all heard it: the age- old “rule- of- thumb” for weight loss rule states that a total energy deficit of 500 calories per day, adding up to 3,500 calories per week, is required to lose 1 pound of body weight. However, this calculation assumes that the 1 lb. loss is almost exclusively from fat.1,2  However, researchers have consistently found that muscle mass is also lost during weight loss, contributing to total pounds lost. Weight loss is not as simple as subtracting calories based off of a standard equation.

The methods used to achieve the calorie deficit are important. Not all calories are created equally, so the quality of the calories also makes a difference in how much weight will be lost from fat mass. Body composition and genetic makeup are also two major contributing factors influencing rate and quality of weight loss.

Basically: the 3,500 calorie rule just doesn’t quite cut it.

Weight Loss With The 3,500 Calorie Rule

Your starting body fat appears to make a difference when it comes to weight loss. For people with a high initial body fat percentage (in both leaner and obese subjects), this equation works relatively well.4 However, in subjects with lower body fat (less than 66 lbs. from fat) the 3,500 calorie equation was more than what was required to produce a 1 lb. total weight loss, because muscle is less energy dense than fat. Men tend to have lower body fat percentages than women, which is one reason why they are generally able to lose more weight at the same given calorie deficit.

This is good news! Because your body fat decreases when you “diet,” (we aren’t a huge fan of this dirty word, but it serves a purpose here) you won’t need to continue subtracting calories at the same rate. Because you will have a greater proportion of muscle to fat than you did before, you will be able to continue losing weight while subtracting less than 500 calories.{4}

chicken portion size

If you kept subtracting calories at that rate, you would eventually be down to 0 calories.

You will eventually need to continue to decrease your calories through diet and/ or exercise as you continue to lose weight, as your metabolism will eventually slow/ stall. Studies have shown that the rate of weight loss is not linear (which is true for progress in almost any form), meaning that you will not continue to always lose specifically 1 lb per week as your body adapts to a calorie deficit over time. 5

Hold on….

Before you start to worry about your metabolism burning and crashing as a result of your weight loss efforts, a quick note: you should know that a faster metabolism isn’t necessarily better. Usually, when we think of a fast metabolism, that super skinny friend that just eats cupcakes all day comes to mind.

However, heavier people actually tend to have faster metabolisms because they are literally carrying around more weight, so their bodies need to work harder to sustain that mass. Therefore, as you lose mass of any kind, your metabolism will slow a bit, though this happens to a greater extent when the loss is more from muscle than body fat. Find out more about maximizing your basal metabolic rate and minimizing the loss of that precious fat- burning muscle in the following sections of this article.

Basically, don’t get wrapped up on the slower metabolism thing, and do continue to throw uneaten cupcakes at your genetically gifted friends.

Key Rules for Fat Loss

How To Lose Weight Fast

…You can’t. If any product or diet boasts rapid and extreme results: RUN! FAST weight loss results are not LASTING results. The idea of a desired effect happening very quickly is enticing, but not sustainable.

More importantly, consider “minimal effective dosing.” So many factors play into our individual metabolisms, as you can see. Therefore, it is important to recognize that the calorie deficit needed to result in weight loss for YOU may vary widely from someone else’s. Instead of jumping right into running for an hour per day and slashing your calorie intake, try only removing 200- 300 calories from your diet first, and only slightly increasing your activity level. You may be surprised to find that your minimal effective dose for weight loss is much less than expected!

If you did jump right into a massive calorie deficit, two specific things would happen very quickly:

1. Your body is going to tell you to eat more and/ or move less to compensate. Just for visual simplification purposes, think of your body as a balanced scale that strives to constantly stay in balance:


lose weight quick

When you put/ remove more on one side of the scale and disrupt the balance, the other side wants to move in the opposite direction, creating a negative imbalance. If you slowly add things to the scale in small increments, the scale will eventually reach a new equilibrium, where this decrease in CALORIE EXPENDITURE is maintained at a given CALORIE INTAKE.

However, if you add too much too quickly to one side of the scale, KERPLUNK. A large and rapid negative energy balance makes your scale petition for a new homeostasis. You will need movement on one side of the scale quickly to shift back towards the middle safety ground. This means a large reduction in CALORIE EXPENDITURE (move less) and/ or increase CALORIE INTAKE (eat a lot more because you are now very hungry and exhausted).


lose weight quick

2. You are going to become discouraged and discontinue your plan because it is not sustainable. Don’t do too much too quickly.

If you can’t see yourself eating a certain way in a year from the moment you start, just don’t do it.

High Protein Diet for FAT LOSS

Sometimes, you should believe what you hear.

For instance, when you hear that:  “Not all calories are created equally,” you should believe it. Don’t let anyone tell you that “a calorie is a calorie;” you don’t need that kind of misguided negativity in your life.

In fact, several studies have demonstrated the superiority of high protein diets for promoting fat loss. Let’s define “recommended protein” in order to better understand what is considered to be a high protein diet. The recommended dietary allowance, RDA for protein is recommended at 0.8 g per kilogram of body weight, which translates into about 0.36 grams per pound of body weight.

So if you are 130 lbs., you should be eating about 47 grams of protein per day, according to the RDA value. If you are eating 1,800 calories per day, that means protein is only about 10% of your daily diet, leaving over 1600 additional calories for fats and carbs.

Just to drive that point home… 47 grams of protein looks like this:

chicken portion size

2 Chicken Breasts at 3.5 oz. each


2 Cups of Milk + Protein Shake

fish portion

2 Fillets of White Fish at 4 oz. each

Leaving room for tons of carbs and fat.

Consuming 2 to 3 times the RDA recommended dietary protein promotes a greater loss of weight from BODY FAT. Using the example of that 130 lb person again, that means 94- 141 grams of protein per day.6

Pasiakos et al. conducted an RCT in 2013 to observe changes in body composition during a 21 day energy deficit (diet) within groups of varying protein intakes. The control group consumed the RDA for protein, while other groups consumed 2x RDA or 3x RDA.

rda graph

Average loss of: 3.5 kg (7.7 lbs) for the RDA group, 2.7 kg (5.94 lbs) for the 2xRDA group, and 3.3 kg (7.26 lbs) for the 3x RDA group.

The graph above shows the average changes in overall body mass (from both fat and fat- free mass) after a 10 day weight maintenance period. At first glance, it would seem that the RDA group benefitted from the diet slightly more than 2 and 3x RDA groups between days 27-31. Overall, subjects lost an average of 3.2 kg (7.04 lbs) during the 21 day diet.

rda graph

In the graph above, we can see that percentage of body fat decreased in each group. However, when we look at the total amount of FAT that was lost, the 2x and 3x RDA group lost significantly more than the RDA group. The 2x and 3x RDA groups also preserved more fat- free mass (including muscle) and lost more weight from FAT. The proportion of weight loss due to reductions fat mass and fat- free mass were the same for the 2x and 3x RDA groups.

This means that the subjects in higher protein groups not only preserved more muscle, but lost more fat while on their diets. Because muscle weighs more than fat, the first chart makes sense now; although the RDA group lost slightly more overall body weight, more of that weight was from muscle than fat. 6

Additionally, The higher the proportion of muscle to fat, the more calories you will burn overall.

Therefore, higher protein diets ⇨greater preservation of lean body mass ⇨  higher basal metabolic rate. See more detail in the next section. Even though this is just ONE supporting article, several studies have supported high protein diets to maintain and/ or lose body fat.

Exercise for Weight Loss

You can lose body fat without increasing your activity level, but moving more DOES speed things up, help you to maintain results, and may result in looking really great naked.

Did I just say that?

Aside from diet, other factors play a role in fat loss. In addition to eating a high protein diet, you can speed up the fat loss process and maintain results by incorporating regular resistance training into your weekly routine to increase your proportion of lean muscle to fat. Muscle tissue burns more calories than fat tissue, even when your body is at rest.7

To boost your basal metabolic rate, eat a diet high in protein on a daily basis, and lift weights 3-5 times per week to maintain and/ or build muscle.

Studies which use diet and exercise to achieve a calorie deficit vs. exercise alone have observed similar weight loss effects;7 however, exercise intensity may play a more significant role than exercise duration in regards to achieving weight loss goals.7,8 Therefore, you should consider a calorie deficit that occurs from both calorie intake deficit and an increased activity level, paying special attention to the intensity of exercise.

More to come on choosing exercise for fat loss in future articles, but note this: the best kind of exercise for fat loss is the kind that you’ll actually DO CONSISTENTLY.


Problems with estimating Basal Metabolic Rate:

The other problem with the basal metabolic rate minus 500 rule lies inherently in the inaccuracy of the basal metabolic rate estimates themselves. The Mifflin- St. Jeor equation was found to be the best, most accurate estimate (within 10% of actual measured) in a non- obese adult population without metabolic disease across the lifespan.9 However, the equation begins to fall apart in the obese populations and those with metabolic disease (only accurate about 40% of the time).10

Basically, if an “obese” (BMI >30, not due to lots of muscle) individual wants to use this calculator to help them understand how many calories they are expending per day

In order to subtract 500 calories from that total  to “lose 1 lb of fat per week…” 

They could be grossly over or underestimating the number of calories needed to result in weight loss!

Furthermore, in reference to the literature referenced above, you can recall that leaner, non- obese individuals also would not need to a number as high as 500 calories subtracted from their basal metabolic rates to lose weight, even though the equation used to determine it itself is more accurate for them.

None of these equations take total fat- free lean mass, specifically muscle, into account, although fat free mass was found to be the best single predictor of basal metabolic rate.1,3 Keep in mind that your basal metabolic rate will be higher when you have more muscle than body fat. Similarly, because we naturally lose muscle mass potential as we age, our basal metabolic rate also decreases, and regular resistance training becomes even MORE important to maintain both your muscle and your basal metabolic rate.

How to Use This Info For Weight Loss:

  1. Use our basal metabolic rate calculator to get an estimate of how many calories you “burn” each day, depending on your height, age, weight, gender, and activity level. This calculator uses your basal metabolic rate and activity level to estimate your total daily energy expenditure.
  2. Try a small calorie deficit first by subtracting 10-15% from your total, or 200- 300 calories, through diet alone or through diet and exercise, with a focus on intensity and exercise preference.
  3. Prioritize protein in all of your meals, and make it a point to consume 2- 3 times the recommended daily value. Here’s another sweet article to help you out with some calculations.
  4. ALWAYS consult your physician before beginning any new diet or exercise programs.


  1. Frankenfield, David et al. Comparison of Predictive Equations for Resting Metabolic Rate in Healthy Nonobese and Obese Adults: A Systematic Review. Journal of the American Dietetic Association. 2005.
  2. Roza A. The Harris Benedict equation reevaluated: resting energy requirements and the body cell mass. The American Society for Clinical Nutrition, Inc. 1984.
  3.  Livesey G, Elia M. Estimation of energy expenditure, net carbohydrate utilization, and net fat oxidation and synthesis by indirect calorimetry: evaluation of errors with special reference to the detailed composition of fuels. Am J Clin Nutr. 47: 608–628. 1988.
  4. Hall K. What is the required energy deficit per unit weight loss? International Journal of Obesity. 32: 573- 576. 2008.
  5. Redman L. et al. Metabolic and Behavioral Compensations in Response to Caloric Restriction: Implications for the Maintenance of Weight Loss. Plos One. 4(2). 2009.
  6. Pasiakos et al. Effects of High Protein Diets on Fat Free Mass and Muscle Protein Synthesis Following Weight Loss: a Randomized Control Trial. The FASEB Journal. 27: 3837- 3847. 2008.
  7. Catenacci V. and Holly R Wyatt. The role of physical activity in producing and maintaining weight loss. Nature Clinical Practice Endocrinology & Metabolism. 2007.
  8. Trapp E. et al. The effects of high-intensity intermittent exercise training on fat loss and fasting insulin levels of young women. International Journal of Obesity. 32: 684–691. 2008. doi:10.1038/sj.ijo.0803781.
  9.  Frankenfield D. et al. Comparison of Predictive Equations for Resting Metabolic Rate in Healthy Nonobese and Obese Adults: A Systematic Review. Journal of the American Dietetic Association. 2005.
  10. Wright T et al. Accuracy of resting metabolic rate prediction in overweight and obese Australian adults. Obes Res Clin Pract. 2015 Aug 12. doi: 10.1016/j.orcp.2015.07.008.

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