Wednesday, October 29, 2008

Dieting vs. Dieting + Exercise (and the importance of Activity)

I received an email yesterday titled "A Contradiction?"

Curious, I opened it, worried that I had somehow contradicted myself in a recent email or a blog post.

Luckily, it wasn't me, but rather a fitness celebrity who had written a newsletter that the writer thought contradicted the Eat Stop Eat philosophy.

Apparently, this particular newsletter was using data from a new research trial to suggest some things that go against the Eat Stop Eat philosophy.

Specifically, it was stating that dieting for weight loss was "bad" and that exercising for weight loss is "good". (I love definitive statements like these - talk about over-dramatization!)

And since I love nothing more than sharing my thoughts on research with you, I figured it would be fun to take a look at this study.

The paper was titled "Weight regain is related to decreases in physical activity during weight loss".

In this study a group of women who were obese and in their late fifties were asked to lose weight by reducing their calories by 400 per day for 20 weeks. Then, 6 months and 1 year after the trial the women were reassessed to see how much of the weight they had gained back.


Here is the first claim that the fitness celeb made:

CLAIM 1: When you diet your level of non-exercise physical activity (NEAT) drops spontaneously, even if you don't realize it's happening.

FACT: In the 20 week study there were actually 3 groups of women,

  1. The first group cut their calories by 400 Calories per day.
  1. The Second group cut their calories by only 350 Calories per day, and increased the amount they exercised to make up the 50 calories by doing low intensity exercise
  1. The Third group only cut their calories by 350 Calories per day, and increased the amount they exercised to make up the 50 calories by doing High intensity exercise

What the study found was that a CALORIE DEFICIT (whether by diet or exercise) was associated with a slight decrease in non exercise physical activity.

In this study this was defined as the energy you expend above your Resting Metabolic Rate (RMR) but does not include the energy you expend during your exercise periods. So this could be anything from bouncing your leg, to walking the dog or emptying the dishwasher. Basically, it was ANYTHING that caused you to expend energy other than your assigned workouts periods.

To give you an idea it was calculated as:

Total Energy Expenditure - RMR - the calories expended during exercise (as calculated by the read out on the treadmill.

The average reduction was about 160 calories worth of activity per day, about the amount of calories expended in a 20 minute brisk walk for these woman).

More importantly, the study found that there was NO DIFFERENCE between the group who was dieting and the groups that were exercising in ANY MEASURE.

This includes:
  • Total weight loss
  • Lean mass loss
  • Fat mass loss
  • V02 Max (surprisingly)
  • Resting metabolic rate

  • and

  • Non Physical activity induced energy expenditure

    So when it comes to weight loss, it is the CALORIE DEFICIT that matters, not the way the deficit was created. However it is true that a being in a calorie deficit for 20 weeks seemed to cause these woman to reduce their non-exercise activity levels (But again, there was no evidence to suggest that this was caused by dieting)

    CLAIM 2: The drop in physical activity during the diet was DIRECTLY RELATED to the weight regain 1 year after the diet.

    FACT: In this study people lost an average of 27 pounds during the 20-week weight loss period. 1 year later the average weight regain was 11.5 pounds. Not bad, but not great either.

    It is very important to remember that the purpose of this trial was to investigate whether or not things that occurred DURING a weight loss protocol could be ASSOCIATED with results 1 year later.

    So they weren't looking for the absolute, definitive, you-bet-your-house-on-it cause for weight regain, they were just searching to see if they could find any associations.

    In other words, they did not measure things like diet or exercise during that one-year time between the weight loss and the last weigh in one year later.

    So while there was a slight relationship between the reduction in non exercise physical activity during the study period and weight regain one year later, this does not indicate a direct relationship.

    Now, it gets a little tricky here because we start looking for correlations in data that isn't non-normally distributed. What was found was that while a significant finding, the strength of the correlation may not actually be that meaningful (for my fellow stats geeks we are only talking about a p of -0.4 for the pooled groups.)

    So this tells us that what found was simply an association, suggesting that the people who tended to move around the least while they were dieting also were the ones who tended to put the most weight back on a year later.

    CLAIM 3: There is a difference between losing weight from dieting, versus losing fat with dieting and exercise.

    FACT: Not according to this study. The three groups saw almost IDENTICAL weight loss results. And, they saw almost identical weight REGAIN results.

    CLAIM 4: if you want to maximize your fat loss and keep fat off permanently it is best to follow a reduced calorie diet and make a conscious effort to make sure your activity level does not drop as you lose weight.

    FACT: I could not agree more. Exercise and staying active is still an important part of ANY weight loss program. However when it comes to weight loss, I think the benefits of resistance training FAR OUTWEIGH the benefits of cardio or endurance style training (as I'm sure the author of the newsletter in question would agree).

    So, there really wasn't that much of a contradiction. Our interpretations of the research are drastically different but our conclusions are the same.

    The bottom line is (and always will be) that the best way to lose weight is to find a the easiest and simplest way to reduce the amount of calories you consume, and to follow a weight training routine.

    While most people think of Eat Stop Eat as only flexible intermittent fasting, the truth is that the Eat Stop Eat lifestyle is the COMBINATION of flexible intermittent fasting and weight training. And, the weight training is very important!

  • You don't have to be a gym addict to get great weight loss results, but resistance training does have to be a part of your lifestyle for best results.

    Now, lets take a closer look at this trial, as there were some 'gems' hidden in all of its data:

    GEM #1- the people in this study were women in their late 50's and who were obese (almost 200 pounds) at the start of the study. By the end of the study they lost 27 pounds in 20 weeks, proving that no matter your age...weight loss IS possible!

    GEM #2- Even one year later, with no diet counseling, they were able to keep more than half of their weight loss. Like I said earlier - not great, but not bad either.

    GEM #3, There was no difference in weight loss between the woman who only dieted and those who dieted and exercised. Another example of classic "cardio" style exercise not being any better than simply dieting.

    GEM #4, all groups lost Lean Body Mass, pointing to the importance of resistance training in a proper weight loss program (which they didn't do in this study).


    So in my opinion this was a great study showing that creating a CALORIE DEFECIT will help you lose weight, and that it really does not matter whether or not you get that deficit from a combination of diet and exercise, or from diet alone.


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    Anonymous said...

    Hi Brad,

    first of all I would like to thank you for the stuff you've written, and all of it are good stuff.

    But reading about this ESE and exercise makes me wonder. I don't know whether this is another myth or fact, since apparently you broke a lot of myth about dieting.

    But aren't exercising while fasting will somehow slow down or hinder your muscle recovery rate? I read about this in some fitness magazine a while ago

    Acai Berry said...

    Excellent post! Even though it takes time to read all what you have mentioned the time spent on it worths it. I feel if people balance their diet and exercising they can gain better results.

    Thank you for the lovely post.

    weight said...
    This comment has been removed by a blog administrator.
    Brad Pilon said...

    Hi Anon,

    Muscle recovery is an ongoing process, since you are still eating every single day with Eat Stop Eat, recovery from exercise isn't an issue.

    I hope this helps,


    Brad Pilon said...

    Hi Acai,

    I couldn't agree more...its all about balance.


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