1. YOU HAVE TOO MUCH CORTISOL
Your metabolism is how your body turns calories into energy. So when you say you have a “slow metabolism”, you really mean your body is hanging onto calories, causing unwanted weight gain.
For some people, it could be too much cortisol, known as the “stress hormone.” Normal amounts of cortisol can help you burn fat if it’s working in tandem with other chemicals in your body.
But if you have too much cortisol—like if you’re really stressed out for a long time—your body may think you’re under duress and could need extra energy. which is why it clings to calories.
2.YOUR INSULIN LEVELS ARE TOO HIGH
Being overweight is a cause of insulin resistance and type 2 diabetes, and having type 2 diabetes is linked with problems losing weight.
According to Dr. Roger Adams, PhD, personal trainer, doctor of nutrition, and owner of eatrightfitness.com, insulin helps the body use glucose for energy. “If a person is pre-diabetic, or insulin resistant, the cells fail to respond to insulin,” he says. “This then results in higher than normal amounts of glucose in the blood, which in turn may signal the pancreas to produce even more insulin.”
The result? Elevated insulin and blood sugar levels, which may progress to type 2 diabetes and weight gain.
3. YOU'RE JUST GETTING OLDER
As we get older, our body loses muscle tissue with every passing birthday. Because lean body mass (i.e., muscle) burns more calories than fat even at rest, less muscle means fewer calories burned, and therefore, more stored as fat.
Strength training is key as we age to slow down muscle loss. Dr Adam says “A well-planned exercise program, including strength training, coupled with a slight reduction in calories but an increase in protein, will help slow down the natural process of lean tissue loss.”
4. YOU DON'T HAVE ENOUGH MUSCLE TISSUE RELATIVE TO FAT
If you want to burn more calories while at rest, you need more lean muscle, which means you need to exercise.
Pick up weight training, which builds lean muscle, and try interval training, which the American College of Sports Medicine says smokes more calories than traditional workouts.
Also, focus on eating a healthy diet and getting enough sleep. If you’re tired you’ll have less energy for exercise—and your lack of energy can make you crave energizing (read: high-calorie) foods.
5. YOUR THYROID IS OUT OF WHACK
Your thyroid gland, located at the base of your neck greatly affect your body’s metabolism. So if you don’t make enough of the hormone (a condition known as “underactive thyroid” or “hypothyroidism”) your metabolism will slow down.
6. YOUR ESTROGEN IS LOW
Lack of estrogen typically increases fat mass and decreases lean mass. Studies have shown that weight gain can be, unfortunately, a result of this lack of estrogen.
Estrogen plummets during menopause, which is one of the reasons why women experience a slower metabolism during and after this point.
7. YOU'RE NOT TAKING IN ENOUGH CALORIES
It seems to make sense that if you eat fewer calories you’ll lose weight, right? Not always.
You need enough fuel to keep your body going, otherwise it will slow down your metabolism to conserve energy. “When we continually eat below our basal metabolic rate (BMR), our body may adapt by adjusting the amount of calories we need to function,” says Dr. Adams. “If we eat just a bit less than the BMR, we can lose weight without drastically affecting our metabolism.
However, if we go too far below our BMR for too long, the body may compensate by going into a lower metabolic state to conserve mass.” Focusing on getting enough protein, especially early in the day, can give your metabolism a boost.
8. YOU'RE TAKING MEDICATIONS
Certain drugs can slow your metabolism. Long-term use of anti-inflammatory steroids, including prednisone, can increase appetite and lead to overconsumption of calories.
They’re also associated with insulin resistance, higher blood glucose, and fat storage. Some studies have shown antidepressants to be linked with weight gain due to a decrease in the body’s basal metabolic rate and an increase in appetite.
Beta-blockers to treat high blood pressure slow heart rate and give you less energy for exercise, according to the American Heart Association, so those could play a role in weight gain.