Why Yo-Yo Dieting Is a Bad Idea

Get-Fit Guy explains the damaging, long-term effects of going from fit to fat to fit.

Ben Greenfield
2-minute read

Why Yo-Yo Dieting Is a Bad Idea

The popular book Fit2Fat2Fit chronicles a personal trainer’s journey of starting fit, gaining 70 pounds, then losing it all. (You can click here to watch the ABC report on the "experiment").

Unfortunately, while this may be a nice publicity stint, this type of yo-yo weight gain and weight loss is actually very bad for the body. In this study, researchers at the Mayo Clinic in the UK fed 23 volunteers who were at normal body weight with no chronic disease a diet consisting of lots of ice cream shakes, king-size Snickers Bars, and Boost Plus energy drinks in order to get them to gain at least 5% body weight within 8 weeks. They then had those same individuals increase their activity and work with a dietitian to lose that weight over another 8 weeks.

Sure enough, just about everyone was able to get back to their original body weight and body fat, but unfortunately:

A) They redistributed fat from originally being evenly located across the body to instead being primarily deposited on the lower body – resulting in a less symmetrical appearance.

B) They increased the size of their fat stores. Lower body fat, rather than being added via an increase in the size of fat cells, is more prone to be added via growth in the number of fat cells – which predisposes a person to getting even bigger as their fat storage capacity increases.

C) They decreased the production of leptin (the appetite control hormone), which resulted in more surging appetite cravings and a lower likelihood of keeping fat off in the future.

In summary: Don’t fall for the hype! There are damaging, long-term effects in going from fit to fat to fit! 

If you have more questions about weight gain or weight loss, then ask away at the Get-Fit Guy Facebook page.

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All content here is for informational purposes only. This content does not replace the professional judgment of your own health provider. Please consult a licensed health professional for all individual questions and issues.

About the Author

Ben Greenfield

Ben Greenfield received bachelor’s and master’s degrees from University of Idaho in sports science and exercise physiology; personal training and strength and conditioning certifications from the National Strength and Conditioning Association (NSCA); a sports nutrition certification from the International Society of Sports Nutrition (ISSN), an advanced bicycle fitting certification from Serotta. He has over 11 years’ experience in coaching professional, collegiate, and recreational athletes from all sports, and as helped hundreds of clients achieve weight loss and fitness success.