Diet vs Exercise – What’s Most Important for Weight Loss?


Notes from a seminar I gave Wednesday, February 16:

  • When reducing body weight, dietary change is more important than exercise in the short term (about the first six months).  Exercise alone results in a very small change in weight over the same period.
  • To maintain weight loss over the long term, the combination of diet + exercise is better than diet alone.

This suggests that improving diet should take precedence over exercise when beginning a weight management program, especially if changing diet AND starting to exercise is too much to manage at the same time.  Exercise can be introduced once better dietary habits are established.

General Dietary Strategies

“Eat food. Not too much. Mostly plants.” – Michael Pollan

  • Decrease calories to create a daily calorie deficit.
  • Watch portion sizes.
  • Replace refined carbohydrates and sugar with vegetables.
  • Use a food journal to keep track of how much food you’re actually eating.
  • Eat lean protein.
  • Don’t drink your calories.
  • Include healthy fats in your diet from things like nuts, seeds, fish, olive oil, avocadoes, etc.
  • Eat whole foods as often as possible.  Use meal replacements sparingly or only when necessary – seek the advice of your doctor or dietician.


Exercise does help in the short term, but it’s more important for long term maintenance of weight loss.  Think of it as a way to improve your health and function, reduce risk of injury and disease, and as a moderate (but necessary) adjunct to weight management.

What Type of Exercise is Best for Weight Loss?

  • Circuit Strength Training – performing strength exercises in series without rest between exercises to increase calorie burn.  Resistance exercise also helps preserve muscle while losing body fat.
  • High Intensity Intermittent Exercise (Interval Training) – performing short bursts of vigorous exercise between longer periods of low intensity exercise.


  • Consult a Registered Dietician for specific, individualized dietary advice.
  • Check with your doctor prior to engaging in an exercise program to ensure it’s safe for you to proceed.
  • Seek the advice of a qualified fitness professional if you are unsure about your exercise program.

Learn something new!


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Michael Bento is an Advanced Trainer at the Clubs at Charles River Park. He holds a Masters degree in Human Movement and is certified by the National Academy of Sports Medicine as a Corrective Exercise Specialist and Performance Enhancement Specialist.

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