Tyler Robbins Fitness

Tyler Robbins has his B.Sc. in Biochemistry: Pre-Medical, is a Certified Strength and Conditioning Specialist (CSCS) through the National Strength and Conditioning Association (NSCA), is certified through USA Weightlifting, and a CrossFit Level 2 Trainer.

Diet vs. Exercise for Weight Loss

A simple search of my blog will show you how many times I have written about this topic, but a new study published last month gives us even more insight - and confirmation, into what I have been writing about in the past.

A systematic review and meta-analysis on the effects of exercise training versus hypocaloric diet: distinct effects on body weight and visceral adipose tissue.Abstract

Exercise training ('exercise') and hypocaloric diet ('diet') are frequently prescribed for weight loss in obesity. Whilst body weight changes are commonly used to evaluate lifestyle interventions, visceral adiposity (VAT) is a more relevant and stronger predictor for morbidity and mortality. A meta-analysis was performed to assess the effects of exercise or diet on VAT (quantified by radiographic imaging). Relevant databases were searched through May 2014. One hundred seventeen studies (n = 4,815) were included. We found that both exercise and diet cause VAT loss (P < 0.0001). When comparing diet versus training, diet caused a larger weight loss (P = 0.04). In contrast, a trend was observed towards a larger VAT decrease in exercise (P = 0.08). Changes in weight and VAT showed a strong correlation after diet (R2  = 0.737, P < 0.001), and a modest correlation after exercise (R2  = 0.451, P < 0.001). In the absence of weight loss, exercise is related to 6.1% decrease in VAT, whilst diet showed virtually no change (1.1%). In conclusion, both exercise and diet reduce VAT. Despite a larger effect of diet on total body weight loss, exercise tends to have superior effects in reducing VAT. Finally, total body weight loss does not necessarily reflect changes in VAT and may represent a poor marker when evaluating benefits of lifestyle-interventions.

To summarize:

Calorie restriction (hypocaloric diet) is effective for weight loss. Exercise is effective for weight loss, although not as good as a hypocaloric diet. Hypocaloric diet and exercise in combination is effective for weight loss. Exercise is best at reducing visceral fat (adipose tissue packed in and around our organs).

So what is better for overall health?

Well, both calorie restriction and exercise are effective for improving your health in various ways, and the political answer would be that they are both effective in maintaining overall health, however what most people don't realize is that both have their strengths and weaknesses, pros and cons depending on your goals. Let me explain further.

Diet

  • For the most part, eat more than you burn to gain weight and eat less than you burn to lose weight.
  • Sure, it is possible that genetics can play a role in your metabolism and how you manage various macros (carbs, for example), but if you are gaining weight, then you are eating too much.
  • On the flip side, if you are losing weight, you are not eating enough.
  • Weight loss includes muscle loss, so by restricting calories and not resistance training you are potentially setting yourself up for strength and connective tissue loss.
  • As the above study tells us, dieting to lose weight is not as effective at removing visceral fat as exercise is. I have written about this before - "Skinny Fat" is Dangerous.
  • Losing weight too quickly (extreme calorie restriction) can cause a rebound effect known as the "Set Point Theory."
  • Protein consumption is extremely useful to maintain a healthy body weight. Make sure to increase your overall consumption as you age.

Exercise

  • Most people vastly over-estimate the number of calories exercise burns. This is especially true for individuals who just "show up" to the gym and don't exercise hard enough.
  • Yes, exercise can be helpful in healthy weight management, but it is not some magical formula that can prevent obesity if you do not diet appropriately.
  • Exercise is extremely beneficial for your brain, mood, bones, connective tissues, muscles, etc. Honestly, the list is so extensive, in my opinion, nobody should go without exercise, or more specifically, a well-rounded program consisting of cardiovascular exercise and resistance training.
  • As the study above tells us, exercise is more effective then dieting alone when it comes to reducing visceral fat - fat that can raise the risk of other diseases.
  • When it comes to changing the way you look, exercise is best at it can help increase lean mass (muscle), improve the appearance of your skin/hair, improve circulation, etc.