Below is an article explaining what happens your hair on a diet...more so on a vlcd...
(The science bit...
It's pretty common to lose hair when dieting. Here's why...
Each hair on your head grows for 4-5 years, then falls out. So your hair is always renewing itself. The long growth stage is called
anagen and the short stopping phase that follows is called
catagen. Then the hair falls out, which is
telogen. The hairfollicle then goes back into
anagen and makes a long hair for the next 4-5 yaers.
What happens during weight loss is
Telogen effluvium. It also happens after any stress to the body. Some of your hairfollicles go into
catagen to conserve body resources. So the hairs stop growing and "rest". Once your body feels safe again, those hairs go back into
anagen - but because there was the pause in the middle, the brand new growinghair pushes the old hair out of the follicle. So in reality you have just as much hair as you did before - and it's probably far healthier hair. But the new hairs are short
Normally around 10% of your head of hair is in the
catagen or
telogen phase, in essence resetting itself to prepare for new hair to grow in. Because you have so muchhair on your head, you don't even notice. During weight loss that percentage gets higher, but this is only temporary. Your body starts creating new hair in its normalcycle once it settles into a healthy weight and those hairs start growing again. Remember that hair doesn't reach a long state overnight! So all those new, healthy hairs need time to grow out to whatever length of hair you have chosen.
Usually it takes 6 months for your head of hair to have grown back out to typical fullness. Hair grows around 1/2" per month, so at the 6 month mark, the hair is around 3" long which is enough to seem thick on most heads. Again, it's not that thehairis MISSING during this intermediate time. It's just that it is brand new and growing from scratch.
Copied from here
Weight Loss, HairLoss and Low Carb - Low Carb if you want to read the whole article!)
I hope this article puts your mind at ease.