Does Exercise Help you Lose Weight?

You may have noticed that the one thing we are not sticklers for in our program is clocking in long, punishing hours at the gym.  As we often tell clients- the best workout is the one you'll stick to, which can be anything from a daily walk to yoga, or spin.  Exercise is a vital part of cardiovascular health, mental health, and self esteem.  But as far as moving the scale?  Look elsewhere. As the old saying goes- Abs are made in the kitchen.  Exercise has very little, if anything, to do with weight loss. 

Let's look at what the studies show us (linked in footnotes)-

  • In the absence of dietary change, cardiovascular exercise can only minimally impact weight loss-  averaging around ~6.5 pounds over 30 weeks (1). Where cardiovascular exercise is more helpful is in weight maintenance after weight loss has occurred . 90% of individuals who are successful at maintaining long-term weight loss engage in an average of an hour per day of physical activity (2).  So getting into a routine now means you are more likely to keep off what you lose!
  • But wait, Muscle burns more than fat, so I should build muscle so my basal metabolic rate shoots up, right?  Well yes, muscle does burn more than fat, but not enough to impact your progress. Muscle function is only 20% of your resting metabolic rate which is only 50-70% of your daily caloric burn (TDEE).  So, for example, if you were to increase your muscle mass by 20% (which is insanely high), this translates into only a 4% to 5% increase in resting metabolic rate. On a 200 pound person this equates to about an 80- to 100-calorie increase per day. (3) Basically... an extra apple.

But how is this possible? If I'm burning calories, how can it NOT help me lose weight? The main theories are that -

  •  You aren't burning nearly as much as you think you are and you're "eating back" more than you should.  Men and women typically overestimate their caloric expenditure by 2-3 times actual expenditure (4).  Even when presented with lab-accurate data, subjects used it as a "license to eat"  (5) and ate back what they expended and then some. Fitness trackers like Apple Watch and Fitbit have a relative error rate of calories expended of 24.3% (6)
  • Individuals often compensate for exercise by reducing other physical activity (7).

So should we all cancel our gym memberships and kick back on the couch with a bowl of lettuce?  Of course not- exercise is key in improving heart and brain health, promoting better sleep and balancing your mood, not to mention improving the physical appearance of your body! But unless you love your HIIT and spin classes there's no reason to do high-intensity cardio for weight loss. Quantity is more important than intensity- Volume of exercise predicts long-term weight loss better than intensity (8) .  So take that walk, lift some weights, or try that dance class- but know that your real work is being done in your daily food choices.



(1) Meta-analysis: effect of exercise, with or without dieting, on the body composition of overweight subjects

(2) Role of physical activity in preventing and treating obesity;  A descriptive study of individuals successful at long-term maintenance of substantial weight loss 

(3) The Myth of Ripped Muscles and Calorie Burn 

(4) Normal weight men and women overestimate exercise energy expenditure 

(5)  Licence to eat: Information on energy expended during exercise affects subsequent energy intake 

(6) Assessment of Accuracy of Overall Energy Expenditure Measurements for the Fitbit Charge HR 2 and Apple Watch 

(7) The Effects of Exercise Training on Fat Loss in Obese Patients During Energy Intake Restriction

(8)  Effect of exercise on 24-month weight loss maintenance in overweight women 

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