Breathing. Heartbeats. Kidney functions. All of these things require fuel. Your body requires a minimum amount of daily fuel to keep you alive. It's not just about fitting into those jeans or that little black dress. It can be about living. When people drastically cut calories and chronically undereat, it can become a serious issue. And your body's response may not be what you were hoping for.
I know that there are some fasting diets being touted as a great and safe way to lose weight. That's not what I'm referring to. Fasting is commonly practiced on a timescale of several hours, and can be safe. Our bodies were actually designed to handle short-term fasts (like when we don’t eat during sleep). We also go anywhere from 4–8 hours without eating when we skip meals during life’s busier moments.
However, undereating at an extreme level such as going without food for several days or eating less than the calorie minimum for weeks or longer can put your body at risk for malnutrition. While a well-nourished body can carry enough stored fuel to meet our needs a few months (muscle tissue and fat), our bodies can only store 1–2 days’ worth of glycogen (the body’s carbohydrate stores), which, if not replenished, is quickly used up to maintain blood sugar. After several days of undereating, the body switches to energy-conservation mode, meaning your metabolism slows way down, making you feel tired and edgy. After 48 hours without food, your body runs out of glycogen to power your red blood cells and brain. To meet basic energy needs, your body ramps up breakdown of muscles and organs in addition to fat.
If you're not consuming your calorie minimum (1200 for women and 1500 for men), it can lead to:
- Slower metabolism and lousy side effects.
- Loss of valuable muscles and organs.
- Higher risk for nutrient deficiencies.
With that said, every body is different. If you are trying to lose weight, try to do it in the healthiest way which may not be the quickest. Be patient and take care of your body. You need to use it for a bit longer.