In a nutshell, sugar cravings are chemical reactions or learned emotional responses (or sometimes both) that typically originate from one of these common situations or conditions:
Abrupt weight loss: A common condition that triggers a physiological sugar craving is losing weight too quickly (commonly the result of crash dieting). Your body has chemical sensors that trigger an alarm if calorie intake drops too low or if fat storage drops too quickly, and the brain turns on the craving center to replace those calories.
Emotional need for serotonin: Serotonin is one of the feel-good hormones that gives you that warm, fuzzy, satisfied (and sometimes sleepy) feeling. If your life doesn’t supply you with enough natural happiness (or if you’re clinically depressed), your brain seeks out serotonin elsewhere.
Sugar, conveniently enough, causes your pancreas to secrete a big spike of insulin to control your blood sugar levels. Insulin eventually triggers the brain to produce serotonin. They don’t call sugar a “comfort food” for nothing!
Hormonal fluctuations: Before menstruation, estrogen is low, and as progesterone falls, your endorphin levels are at their lowest. Monthly hormonal fluctuations can explain why many women who experience strong PMS symptoms also have strong sugar cravings — the low endorphin levels cause them to seek out the serotonin burst that a sugar overload can provide.
Inadequate nutrition: If your diet is deficient in certain nutrients, your brain turns on the craving center to try to increase nutrient intake. Your body is programmed to seek out high-calorie (which, in the cave man days, meant high-nutrient) foods, so when your body’s computer senses a lack of nutrition, it turns on the cravings with full force as a survival mechanism.
Learned behavior to mask loneliness, boredom, or self-deprecation: Sugar equals serotonin. If you’re feeling bad, eating sugar can temporarily make you feel better. It’s very easy to learn how to substitute unhealthy eating habits for introspection and personal work. When the inner critic starts scolding you, an easy way to quiet the critic is to drug yourself with sugar.
The same goes for when you’re feeling lonely, bored, or anything else you don’t particularly like to feel. Instead of doing the hard personal work that’s required to change their ways of thinking and interacting with the world, many people take the easy way out and ignore their problems by zoning out with sugar (or sometimes even worse drugs).
Stress: When your body churns out cortisol and other stress hormones all day, you burn up stored carbohydrate (instead of fat) for energy so your brain turns on the craving center to replace that sugar.