Expert: Dr. Bret L. Emery - 4/23/2007

Question
I have a question about metabolism. I am trying to, unsurprisingly, lose some weight. First, I know the general rule is eat at minimum  1200 calories a day in order to lose without speeding down metabolism, but since I am quite a bit smaller than average, 5 foot 0 to be exact, could I possibly go lower without suffering those negative side effects? Also, I was wondering how long it takes one, what with eating less than 1200 cals a day, in order for it to effect ones metabolism. If I dip below that just for a day am I going to see negative consequences?

Thanks so much!
Amanda

Answer
Hi Amanda,
Yes 5'0" is smaller than the average woman, so it does seem to make sense that you should be able to eat less than what is recommended for the average woman (1,200 calories).  

What I do in my practice is measure the individual's actual metabolism, and then design their diet and calories accordingly.  And many times, I find that shorter women have to go below 1,200 calories in order to lose weight because their metabolism is actually lower.  I can't ethically suggest you do this without knowing your metabolism.  But if you decide to go lower, do it slowly.  Start by cutting 100 calories per day for a week and see if it has an effect.

As for the metabolic slowdown that occurs on low calorie diets.  It is a result of cutting calories too far below what is required.  If you cut calories slowly and stop lowering them as soon as you see weight loss, you won't go to low to slow the metabolism.

I would also suggest that one day each week you eat extra calories.  I call this the "day off".  It is a day off of dieting.  It will serve to physiologically up regulate your metabolism by sending signals to the brain that the body is not starving.  it also serves a psychological purpose in that it is a day to not worry about the diet.

Your final question of whether dipping too low one day can cause a slowdown in metabolism, my answer would be yes.  Anytime the body senses a lack of calories, it sends a signal to the brain.  Now, you may not see any detrimental effects in regards to weight after just one day, and the metabolism may upregulate again at the next meal.  However, if one was to cut calories too low for multiple days in a row, there would begin to be negative consequences on metabolism.

One way to offset the lowering of metabolism is to exercise.  Exercise elevates the metabolism.  You may already be exercising, but if not, you may want to add it to your weight loss program!

I hope this helps, and please do not hesitate to ask if I can elaborate or clarify anything.  Best of luck with your weight loss!

Dr. Bret
www.doctoremery.com