Expert: Joanne - 11/29/2008

Question
I have seen this addressed a bit but I still don't quite understand and am at
my wits end.  Getting very depressed.  For about 2 + years I would eat
around 300 or so calories one day and then eat 'normally' (but healthy...so
probably around 1200-1400 calories) the next day..after a year or so of this I
started increasing the low cal days to 2-3 days and then I'd have a 'normal'
day.  It was the ONLY time in my LIFE that I was ever able to lose weight.  I
got very skinny 118 lbs (I am 5' 9) and was so happy with this.  Then the
unthinkable happened.  I started to GAIN weight.  I measure/weigh portions
and do not eat junk food.  I freaked out and started to eat even less.  I only
ate vegetables (dry roasted...no oil).  I was afraid to step on a scale to see
how much I had gained but my clothes were getting tighter.  When I finally
weighed myself I saw the awful numbers...In about 7 months I gained 40
pounds!  I am so depressed and confused.  I feel like my body has betrayed
me once again (I used to eat very little and run 5 miles a day and didn't lose a
pound! )  I just don't understand...

Answer
Rebecca

Firstly, I would suggest that you go and get checked by a doctor to make sure that there is no other reason for your weight gain, and while there, I think that this could be a good opportunity to talk to someone about getting some help addressing these disordered eating patterns.  I'm especially concerned at how dramatic your weight gain has been if you truly have been eating so few calories!

It can be common for people to gain weight slightly when they are starving themselves if you are continuing to take in calories.  You have a basal metabolic rate (BMR), and it is a value given in calories (differs for every individual), and basically, it is the minimum number of calories you need to eat every day, in order for your body to carry out all of its functions, but this is a value for your body at rest.  You then need to add on calories for movement that you make, exercise, whether or not you need to use a lot of energy to keep yourself warm, etc.  When your body is only getting a very small number of calories from food everyday, it has an inbuilt mechanism to protect itself.  In 'starvation mode' the body slows down its metabolism in order to make the most of calories that it does receive.  Your BMR drops as the body will cut out processes that aren't essential for life, and cut corners on other processes where it can, meaning that fewer calories are necessary on a daily basis.  The body also tends to protect its fat stores over muscle and lean tissues, and will quite happily breakdown muscle to in order to obtain extra fuel before dipping into fat stores.  Lean tissue and muscle tend to burn more calories than fat stores as well, so loss of muscle mass also lower metabolic rate.  

This means that your body had to survive like this most days, and your metabolism has slowed accordingly, but on the days when you eat more normally, your metabolism doesn't switch back and automatically starts burning more calories, but instead can store more calories.  The only way to rectify this situtation is to eat a normal diet of definitely no less than 1200 calories, but better to be above 1500, every day.  It should be split up into meals with a couple of snacks spread between meals so that your body is can rebuild itself, and get used to being fed well regularly.  During the time that this is going on, it is important not to begin to starve yourself again, or attempt to burn off too many calories through exercise as your metabolism will struggle to recover.

Joanne