Have a question for our experts? Ask it here!
The expert answers:
Craving for sweets is very common and complicated, with many biological sources -- some that no one yet understands. But without a doubt, one very important source of sugar cravings is the intricate relationship of blood sugar, insulin and serotonin --which you probably know is the neurotransmitter that is the target of antidepressants like Prozac.
When you eat a high-carb diet, your blood sugar levels are high; this causes your body to produce high levels of insulin. High levels of insulin cause a lot of health problems, but people like this state because it brings the amino acid, tryptophan, into the brain: Insulin is like a tryptophan escort service!
Tryptophan, in turn, is the raw material for serotonin, which is one of the neurotransmitters that help us feel good.
Bottom line: High insulin levels increase serotonin in the brain, and we like it.
For many people, sugar is an everyday, socially acceptable way of self-medicating their moods. Initially, when you decrease carbs, your blood sugar and insulin levels drop; this may make you really crave sugar. This also happens during the course of the day when you are hungry. Your low blood sugar may make you want a quick fix of sweets.
When people tell me they want sugar because it tastes good, I often point out that, if it's the taste they're after, they would eat slowly, savoring each morsel. Most people just shovel it in to satisfy their cravings! Hang in there. Over time, your body will become resensitized to lower levels of insulin.
These lower levels are actually very normal for the body. Your brain cells (and all the cells of your body) actually will readapt, and this normal, lower level of insulin will be all you need to get plenty of tryptophan into your brain.