Have sensible people been wrong all this time about crash diets? Could it be that the extreme regimens Hollywood stars follow are actually healthy, effective and long lasting?

...not really!

If you've been reading the stories coming out of UK newspapers Timesonline and The Daily Mail, you may have been lead to believe that crash diets do work.

But as so often is the case in these proclamations, the devil is in the details. In this case, the detail is the definition of crash diet. It appears that Dr Susan Roberts - the researcher behind this claim - has a different idea than I do of what constitutes a crash diet. Let's explore:

Sensible Healthy Crash Diets - Oxymoron?

According to Dr. Roberts, there are both good and bad crash diets. Roberts states the lemon cleanses, sub-1000 calorie and otherwise extreme diets are still verboten. Evidently, a minimum of 1,200 calories per day (1,800 for men), with adequate protein and low glycemic carbs, is still in the crash zone (the good crash). Huh?

Study Summary

There were 2 groups of subjects - one group cut 10% of calories, while the other group cut 30%. Roberts noted that after a year, they wound up pretty much the same.

Note: I would like to see the curve for this one though. My guess is that the 30% group lost more in the first 6 months, and then gained more in the latter 6 months.

Some Valid Points

My disagreement over the definition of crash aside, Dr. Roberts did have some cogent thoughts regarding who might benefit from a more drastic change. She notes;

The trouble with slow diets is people tend to feel they are getting nowhere and give up. Fast keeps you excited and feeling like you're making progress...Disinhibited eaters [a psychological term referring to people who give up on diets easily when presented with food opportunities] actually did really badly on the 10% diet.

This is consistent with observations in my own line of work. For people who have strong cravings and have a difficult time moderating, sometimes it is better to just eliminate, rather than moderate.

But still, the fact that such a prominent researcher labels a 1,200 kcal diet as a crash gnawed at me a bit, so I decided to email and ask her about it. Dr. Roberts was prompt and courteous in her response and offered this...

I've been trying to redefine what is meant by crash dieting to make a crash diet mean 'fat loss that is as fast as reasonably possible'. So right, 1200 calories is certainly not starvation, but in my research and clinical experience is about as low as most people can sustainably go.

Aside from research at Tufts University, Dr. Roberts' thoughts can also be found on The Daily Beast Blog and in her book The Instinct Diet

Take Home Message

  • Removing emotional barriers and setting the right mindset is crucial for fat loss and optimal health - regardless of the path you take.
  • Nutritional habit changes are highly individual. The number of calories you should drop depends on your body weight, body type, activity level and individual lifestyle and preferences.
  • The best diet is the one you can stick with.

How do you define crash diet?