Let’s take a look at some of the factors that can lead to a less-than-stellar metabolic rate.


1. An underactive thyroid: Also known as hypothyroidism, this can occur when your thyroid isn’t making the right amount of hormones. And these hormones are known to increase your resting metabolic rate. No surprise then that weight gain is a classic symptom of an underactive thyroid.

2. Sleep deprivation: Remember that studies don’t always agree and the issue of sleep deprivation and metabolic rate is no exception. But there are several studies that have shown an association between short sleep duration and slower resting metabolic rate. That’s enough for me to make an effort to get to bed a little earlier than usual!

3. Certain medications including Seroquel (quetiapine), risperidone (Risperdal), and olanzapine (Zyprexa) can reduce resting energy expenditure (another way of describing your metabolic rate at rest).

4. Loss of muscle due to inactivity and age over the years: It can happen to anyone of us. Life gets busy, and although we may still make it to the gym, we spend a lot more time sitting that we used to. And, over time, we lose some of our muscle mass, replaced by the less metabolically active fat tissue. And that, my friend, is a recipe for a slower-than-it-used-to-be rate of resting energy expenditure.

5. Weight loss: And along with the good, comes the bad. Weight loss can bring with a reduction in what is called fat-free mass (aka muscle). And just like with age and inactivity, you find yourself with a lower metabolic rate just when you could use a higher one to help keep your weight where you want it. If that is the situation you’re facing, it might interest you to know that resistance training can help preserve muscle and metabolic rate, even when you’re losing weight.

6. An (overly) low protein diet: There is some evidence that eating protein helps reduce the loss of muscle mass seen with aging and weight loss. And because carbs can be relatively easy to grab on the go (toast, muffin or a bowl of cereal anyone?), sometimes a busy life means a protein intake that doesn’t quite do the job. (Just make sure you don’t overdo it. Too much protein comes with its own problems.)

7. Less than stellar cardiorespiratory fitness: In other words, your aerobic fitness level influences your resting metabolic rate. Lower your fitness, and you lower your metabolic rate. This fairly simple equation also helps explain why 20 minutes on the treadmill may give you more than 20 minutes worth of benefits. By increasing your metabolic rate at rest, working out your heart and lungs can be the gift that keeps on giving.

8. Less than ideal dietary composition: In some studies, eating saturated fats (a la the western diet) led to a lower rate of resting energy expenditure than when eating monounsaturated fats (a la the Mediterranean diet). (And for another interesting related fact, levels of anger-hostility went up when eating more saturated fats. Another reason to throw a handful of nuts rather than a handful of bacon bits on your salad?)

Bottom Line: When it comes to our health and our weight, there are a lot of factors that we can’t control - our age, our gender, our race and our family background. But there are some metabolism killers that you might just be able to address. So, get the green light from your doctor, and then see whether changing your lifestyle (diet quality, physical activity, and sleep patterns) can give your metabolism a boost in the right direction.