Many of us believe that the key to a lean body is to eat less and exercise more. To understand why it’s a little more complex (yet simpler, in my opinion) than that we must understand how the body uses energy/calories. The total amount of calories that you burn in a day is known as Total Daily Energy Expenditure (TDEE).

First, the majority of the calories that you take in per day, assuming you eat regularly balanced meals throughout the day, are used to maintain basic body functions like breathing, circulating blood, building new cells, digestion, and even thinking.  This is known as your Resting Metabolic Rate (RMR) and accounts for roughly 60%-75% of the calories you burn in a day. This amount is affected by age, size, gender and body composition (how much fat versus muscle you have).

Next you have your daily activities that are required just to survive like preparing meals, cleaning the house, doing the laundry, going to the grocery store, etc. This is known as your Non-Exercise Activity Thermogenisis (NEAT).

There is also the Thermogenic Effect of Food (TEF).  Ever notice that when you are cold, if you eat something, you warm up?  This is because your body burns calories to chew, digest, and store the food/nutrients you eat. Of all the macronutrients – carbohydrates, fats and protein – protein has the largest thermic effect on the body.  TEF accounts for about 10% of the calories you consume in a day.

Finally, if you exercise, there will obviously be some extra calories burned to carry out that activity.  If you’ve ever watched the calorie counter on a stair master or treadmill you know that it is a lot easier to consume 300 calories than it is to burn 300 calories!

If we further evaluate the 4 ways we burn calories above we can understand how to manipulate them in various ways.  For example, if we want to increase the number of calories, we burn through the thermic effect of food then we should consider adding more lean protein to the diet and less fat.  Protein raises the TEF the most while fat raises it the least.

Increased daily physical activity definitely has the potential to burn more calories.  However, many of us are stuck in jobs that require very little activity and there are only so many hours in a day to get your workout in.  Of course, you can take a morning walk before work, take another at lunch and another after dinner.  You could do things like choose a parking spot at the grocery store far from the entrance that would require more walking, you could get up and change the channel on the TV manually rather than use the remote (do tv’s even have that option??!?!), and you could wash your car by hand versus going through the car wash.  All of these activities would increase your NEAT.

Now let’s look at increasing our RMR.  Is it even possible?  Yes!  It is a well-known fact that muscle tissue is very metabolically active, meaning it uses up calories to stay alive, even at rest.  Therefore, the muscle mass you have on your body the more calories you burn even while lying on the couch!

It goes even further than that though.  A recent study published in the Journal of the Federation for American Societies for Experimental Biology found that after weight training, muscles create little bubbles of genetic material, known as extracellular vesicles, that flow to fat cells and jump start fat burning. Several other studies have demonstrated that the body’s ability to burn fat is increased for up to 24 hours after a weight training session. After even just 6 weeks of heavy lifting, for example, muscles will burn more calories just because they are larger.

I could go on and on about the benefits of lifting weights in the prevention of osteoporosis, dementia, postural dysfunction and age-related muscle atrophy but I will save that for another day.

If the amount of time you have in the gym is limited – lift weights!



Mechanical overload-induced muscle-derived extracellular vesicles promote adipose tissue lipolysis

Ivan J. Vechetti JrBailey D. PeckYuan WenR. Grace WaltonTaylor R. ValentinoAlexander P. AlimovCory M. DunganDouglas W. Van PeltFerdinand von WaldenBjörn AlknerCharlotte A. PetersonJohn J. McCarthy  See fewer authors 

First published: 25 May 2021

Charlotte A. Peterson and John J. McCarthy are Co-senior authors.


Lifting Weights? Your Fat Cells Would Like to Have a Word. A cellular chat after your workout may explain in part why weight training burns fat.