Metabolic Rate Myth – Is Changing Your Metabolism Possible?


I have to admit it, I fell for it too. I fell for all the hype and hoopla that saturates our fitness culture about metabolism. I studied long and hard how to boost it, grow it, speed it up and protect it. It was the focus of any of my weight loss videos and articles and it was of great concern that none of my clients “crash” their metabolism with some stupid diet.

These days things are different. I could care less about my metabolic rate. All of my diet and exercise strategies are done for anything but metabolic benefits. Here’s why:

There Are Actually 2 Types of Metabolism
Actually there are lots of different types of metabolism. There is carbohydrate metabolism, fat metabolism, sugar metabolism and so on. In our fitness culture, we tend to talk about 2 different types: BMR and TM.

BMR is basal metabolic rate and TM is total metabolism. BMR is the total number of calories you burn just to maintain your body as it is, and TM is the total number of calories you burn, period. Neither one is worth losing sleep over.

Total Metabolism Is Quick and Easy To Change
Your total metabolism is really quick and easy to change. It’s like a raging river where the rapids are always changing shape. Just simply stand up right now and do jumping jacks. Your total metabolism just increased! Eat something, anything at all and your total metabolism will also increase. But if you stop moving or eat less, you will burn fewer calories and hence “lower your metabolism”.

All Foods Increase Total Metabolism
All foods increase your total metabolism regardless of what they are. Anything from fried Twinkies to organic salmon requires some sort of energy to digest and thus will “boost your metabolism.” Some foods boost more than others because they require more energy to digest (like salmon) but unless you’re making a radical change in your diet, the differences are nothing to get all excited about.

All Physical Activities Increase Total Metabolism
Do something, anything at all, and you will increase your total metabolism. You can do any activity you like be it cardio, weight training or wrestling in a pool full of Jell-O. The longer or more intense the activity, the more calories you burn and thus the more you “boost your metabolism.”

EPOC Is Hard To Track or Account For
I used to look to certain exercises for the so-called “after burn” or what is known as the Excessive Post-Exercise Oxygen Consumption. There are many factors that influence how long or how intense the E.P.O.C is. It’s a very unreliable calorie burn. Sometimes your E.P.O.C could last for hours and burn hundreds of calories, other times it might last 20 minutes and burn off a few potato chips. I simply figure it’s a bonus burn, but nothing I’m going to count on simply because it’s very hard to track and keep consistent.

Your BMR Isn’t Going Anywhere Anytime Soon
While total metabolism can change at the drop of a hat, your BMR is like a glacier, moving and changing ever so slowly. Plus it’s important to note that most of the factors that determine your BMR are not something you can intentionally change or control. Your age, gender, height, somatotype, and even genetics all account for the lion’s share of what causes your BMR to be where it is.

Muscle Plays a Minor Role In Changes To BMR
It’s true that lean body mass plays a role in influencing your BMR but muscle is only a part of what makes up your lean body mass. In the movie of metabolism, muscle is a bit character. Your organs, blood, water, skin, bones and everything else that’s not fat is a contributing factor.  Muscle is just one player on the massive team that makes up your BMR. In the past, I believed that a pound of muscle burned hundreds of calories. Now though, the figures are coming down to as little as 15-20 calories per pound. A few added pounds are hardly anything to get excited about.

You’re Probably Not Going To Change Your Muscle Mass Quickly
Let’s face it, unless you’re a young adult male who has never done any exercise, or someone on drugs, you’re not going to be packing on 30 pounds of muscle this summer. At the same time, unless you are going to starve yourself and give up all activity for 4-5 weeks you’re not going to drop a whole lot of muscle either.

The amount of muscle on the human body is slow to change even with most diet or exercise changes. What this means is that because most of the factors in your BMR can’t be controlled and that the few factors that can, are not going to change very fast, your BMR isn’t gong to go through any big changes anytime soon. It would be like expecting a glacier to come racing through town.

Food Is a Relatively Minor Player in Maintaining BMR
Lots of diet strategy is aimed at boosting or protecting your metabolism. Most of it isn’t really going to do anything. Eating frequent small meals, never skipping meals, and eating at only certain times of the day has little, if any, effect on BMR. It’s like changing the course of that glacier with an ice pick.

Your Metabolism Doesn’t Control Your Weight
Finally we must recognize that either BMR or TM is only half of the weight control equation. They are only focused on the calories going out of the body and while that’s 50% of the game, it’s the relationship between calories out and calories in that makes the difference.

You can have the metabolism of a hummingbird and still gain weight. You can have the metabolism of a slug and lose it. Granted it would be easier to be like the hummingbird, but a higher BMR or even TM is in no way a guarantee that fat loss will occur.

So that’s why I don’t give a hoot about metabolism any more. Instead, I focus on something that is far more important and influential to weight loss and every fitness goal imaginable. Funny enough, few people never pay much attention to it. I’ll cover that in my next article.

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About Author

Matt Schifferle

My name is Matt Schifferle and I'm an A.C.E. Certified Personal Trainer, CrossFit Level 1 coach, underground strength coach and I'm a 5th degree black belt in Taekwon-Do. I specialize in outdoor and playground based underground and CrossFit style bootcamps. See my profile page for more information!


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    Before I start this post, I’d like to state that I’m one picky guy. I do everything precise and write everything down (eating, training, etc). I’m one of those guys who only eats broccoli, rice and chicken. That should give you an indication 🙂 Anyway, I’m a 19 year old dude from Holland, soon to turn 20 who has been weight lifting like a wimp for about 3 years (on and off). At the time I was weighing about 226 pounds at 6 feet tall. My body fat was around 24%. I started with intermittent fasting (16 hrs/8 hrs) and going to the gym 7 times a week. 5 days were devoted to strength training, hitting each body part twice a week (split workouts) and doing cardio twice a week. All the training I did was fasted, early in the morning. My BMR was around 2,000 calories per day. So I dropped it to 1,500 calories while combining this with exercising EVERY day. I guess my caloric deficit was pretty large. Here is my training routine:

    Monday: 1.5 hours of weights, 30 minutes of cardio
    Tuesday: 1.5 hours of weights, 30 minutes of cardio
    Wednesday: 1 hour of cardio, 30 minutes of interval training
    Thursday: 1.5 hours of weights, 30 minutes of cardio
    Friday: 1.5 hours of weights, 30 minutes of cardio
    Saturday: 1 hour of cardio, 30 minutes of interval training
    Sunday : 1.5 hours of weights, 30 minutes of cardio

    Before you say this is too much, I need to tell you that apart from going to the gym (I DO NOTHING ELSE), I sit on my butt all day playing video games! I like going to the gym and I’m now 5 weeks in and still feeling pretty good. So I don’t think I’m destroying myself. After 4 weeks my weight dropped by 14.7 pounds. Of which 0.8 pounds were muscle and 11.2 pounds were body fat. The rest was water weight. My body fat dropped to 19.9%. Of course, I did expect to lose some muscle when I’m in such a heavy caloric deficit.

    After this I decided I wanted to weigh myself every week to see the results. I eat about 1,400 to 1,500 calories during my 8 hour feeding window. After training, I have some simple sugars with a protein shake and some slow burning carbs. The rest of the day it’s mostly rice broccoli and chicken. My macronutrient breakdown is 40% carbs, 40% protein, 20% fat.

    This last week my weight dropped only by 2.6 pounds with 0.2 pounds coming from muscle and 1.5 pounds from fat. My body fat only dropped by 0.5%. I am weighing myself on the SAME DAY with an empty stomach at the same time in the morning on the gym scale which is a Bioelectric Impedance Analysis, or BIA scale. I’m not really sure how accurate that scale is though. Anyway, according to the scale my progress of losing fat has been decreased by 50% While I’m still losing the same 0.2 pounds of muscle every week. So in 4 weeks I would only be losing 10.4 pounds, of which 0.8 pounds is lean muscle tissue with only 6 pounds coming from body fat!

    So my question is why am I suddenly losing a lot less weight when my BMR has barely changed? I have a big caloric deficit by eating less calories and working out the exact amount I was for the last 4 weeks. However, my weight loss has dropped to only 2.6 pounds a week while still losing the same amount of muscle while eating 1,400 calories instead of 1,500 calories per day. My main questions are:

    1. I read a lot about metabolism. Is it a myth that it can slow down even though I’m in a pretty huge caloric deficit?
    2. Am I counting my calories correctly? I am eating simple stuff and using a diet tracking app (40% protein, 40% carbs, 20% fat).

    My plan is to cut to 15% body fat and then start taking creatine, while slightly increasing my calories and hopefully make some big GAINS. But this suddenly seems very far away for me. Any tips would be greatly appreciated!

    • shapefit

      Patrick – Here are a few tips to help you. The first thing I recommend is not training in a fasted state, especially when weight training. Your body has fasted for 8-10 hours during the night and is in a highly catabolic state (breaking down) when you first wake up in the morning which means it’s screaming for nutrients. Eating some slow burning carbs like oatmeal with whey protein is an ideal meal at this time but at the very least, you should drink a protein shake or even have a BCAA (branched chain amino acid) drink before heading to the gym. You want to get in these key amino acids quickly into your body before you start training hard. If you keep working out in a fasted state, you risk burning up even more of your hard earned lean muscle tissue.

      To answer your first question about metabolism, I think you’re training way too much and not eating nearly enough calories for your height/weight. Your body is screaming for more fuel so it’s important to eat more. You can use our calorie calculator to see how much you should be eating each day.

      For your second question, if you’re using a reliable diet tracking app then it should provide accurate nutritional information for the foods you’re eating.

      If you need any additional help with your diet and training, I highly recommend posting your questions in our free fitness forum and our members should be able to assist you further. Best of luck to you 🙂

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    I’m a 19 year old female and in about 3 months I lost 10 pounds (from 130 to 120) at a height of 5’3″. I ate 1,300 calories per day with no exercise and was able to lose at a rate of 3 pounds a month. However, once I got to 120 pounds, I can’t lose weight no matter what I do anymore. I lowered my calories from 1,300 to 1,100 then down to 800 with no results. If it’s really calories in versus calories out then what am I doing wrong?

    • shapefit

      Anna – Your body is probably in starvation mode and hoarding fat from such low calories. When you drop your calories too low, your body gets shocked and starts to maintain adipose tissue (body fat) and burn lean muscle tissue for fuel which is a double whammy! The key is to find the right balance of enough calories per day along with implementing resistance training exercises to build lean muscle mass which is the engine that burns calories and keeps you lean. I highly recommend fueling your body with at least 1,300 calories per day (actually 1,500 calories would be ideal) and then add in weight training to your routine along with a little cardio exercise to burn off any extra. This will keep your “engine” (metabolism) running hot and I’m sure you will start seeing great results!

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    You cannot speed up your BMR so as to lose body fat. But you can prevent your BMR from slowing down below the norm as a good strategy for losing weight.

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    I’m 41 years old and losing the battle. In 6 years I have gone from a size 6 to a size 10 and have gained 25-30 pounds. I am 5’3″ and I’m really starting to look short and round. I have to keep my protein low (around 45-50 grams per day) so I feel like I’m stuck. I would be fine doing cardio and do a good deal of it, but I just can’t seem to take any weight off. I get very frustrated and lose track. I can get down to about 158 pounds and then I plateau. What can a woman over 40 do to lose weight?

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    Love your article! I’m nearly 70 years old and was diagnosed with type-2 diabetes on May 1st 2018. The doctor prescribed 5 units of insulin and sent me home. Bad enough I have to do finger sticks for blood sugar. I wasn’t going to do the insulin. I started a 1,000 calorie per day diet along with walking 4 to 6 miles every day. My blood sugar is within normal limits and I’ve lost 70 pounds! When I stop losing weight, I increase my calories and keep walking. I now weigh 145 pounds and still no insulin. My initial A1C was 13.4 and the latest was 5.7 (normal is 4 to 6) and today’s date is November 27, 2018. Losing weight is doable if you listen to your body!

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