Trying to stay on track with a diet? Be careful of these sneaky metabolism killers.

By Katherine Flynn
August 22, 2016

“Metabolism” is the system in the body that converts calories to energy. Many variables contribute to your metabolism, including heredity, gender, and age.

A metabolic slowdown leads to a build-up of calories. Once your metabolism slows and the calories build up, they will be turned into fat, leading to weight gain.

We talked with our Nutrition Editor, Sidney Fry, MS, RD, to discover what causes our metabolism to slow down and how to avoid these pesky metabolism killers. By following this list and improving your diet and daily habits, you’ll be able to keep your metabolism in check and even boost it.

You're skipping breakfast

We all know this is the most important meal of the day but with traffic, meetings and getting kids to school, this meal can suffer. We might not think of it as a big deal but it greatly affects our bodies, thus our metabolism. “Our metabolism slows down during sleep. You need to break the metabolic fast to give your body an energy boost,” says Fry. However, this doesn’t mean grabbing a sugar-ladened muffin or donut on your way out the door. “Sugar and refined carbs will cause you to crash again later. Choose foods high in protein and fiber, and low in added sugars,” says Fry. Check out these breakfast options to wake up your metabolism in the morning. 

Photo: Getty Images

You're eating too many refined carbohydrates

Refined carbohydrates are very different from carbohydrates found in whole grains, fruit and vegetables. Don’t reach for refined carbs like white flour and sugar. “Those are quick to digest, meaning your body uses less energy to break them down. The higher-in-fiber whole grains slow down digestion and make your body work harder to break down nutrients,” explains Fry. Simply, whole grains, fruit and vegetables naturally boost your metabolism while refined carbs and sugars will instantly kill it. Thus, making you feel hungry sooner causing you to eat more empty calories later leading to weight gain.


...Or high fructose corn syrup

This hyper-processed sugar isn't only lurking in that soda – it's found in snack foods, condiments, ice creams, and crackers, too, explains Fry. Sugar is hidden everywhere with many different names, and high fructose corn syrup (HFCS) is one of the biggest metabolism culprits. “Long-term consumption of HFCS has been found to increase body fat at a higher and faster rate, increasing the risk for metabolic syndrome,” says Fry. “HFCS, unlike table sugar, is a free and unbound sugar molecule that is more readily absorbed and utilized meaning the body has less work to do to process it thus slowing down your metabolism.” It’s important to note that HFCS should not to be confused with the fructose found in fruit, which comes with metabolism-boosting slow-digesting fiber, explains Fry.

You aren’t eating enough

You need calories to boost your metabolism and lose weight. Not eating enough is almost as bad as eating too much to kill your metabolism. If you don’t eat enough for your body to simply function or you are depriving yourself, you body will slow down your metabolism and start to break down calorie burning muscle. Your body needs calories to get energy and if there aren’t enough to power your body, your metabolism has no choice but to stop. In order to combat this issue but maintain your diet, try eating small and healthy meals throughout the day to keep your energy steady, thus boosting your metabolism. 

Photo: Getty Images

Your exercise regimen is stale

We’ve all had that burst of energy and motivation to workout daily and eat healthy. However, for most of us, how long does that actually last? In order to keep your metabolism steady, an exercise plan is crucial.

But when it comes to metabolism, it's important to mix it up according to Fry. “Make sure you don't get into the same routine, running the same route or walking the treadmill at the same pace every week. Add in some strength classes or exercises, and change up your cardio routine if you can. Even when your body is at rest you are burning calories, “ said Fry. In order to avoid slowing down your metabolism, find different exercises that work for you but include muscle, cardio, and strength work to not only burn calories but to keep you metabolism working.

You aren’t getting enough protein (or iron)

Protein is a tricky subject. For most of us, we consume enough protein to get us through the day. However, there is always a correlation between a steady metabolism, a healthy lifestyle and a high intake of protein. We suggest making sure you have protein in almost every meal only if you maintain a healthy exercise schedule. If you are just beginning to exercise or change your diet, avoid weight gain by slowly adding protein with these protein-packed snacks.

Iron can be found in lean meats and plant sources such as beans and spinach. In order to keep your metabolism buzzing, consume iron-rich foods because they carry oxygen to your muscles that in turn burn away at fat. Iron overall is good to include in a healthy diet while trying to improve your lifestyle.

You’re drinking too often

One glass of wine at night won’t kill you. However, if you’re drinking every night of the week, it can kill your metabolism. Once alcohol is in you system, it hinders your body’s fat burning speed and thus burning less fat and slowing down your metabolism. If you are trying to boost your metabolism, stick to water and if you do have a drink, try have heart-healthy red wine instead. 

Photo: Getty Images

You're not sleeping enough

Our bodies are constantly working and in order for them to rest, you must recharge your batteries. Sleep deprivation contributes to numerous factors that can kill your metabolism. Without digging too deep into how our body’s natural sleep cycle functions, essentially sleep moderates a chemical known as leptin that signals to our brain that we are satiated. Thus less sleep equals a lower amount of leptin which leads to overeating and a slower metabolism. It’s a slippery slope and can easily form a habit without us even noticing besides constant yawns and large amount of coffee the next morning. Another thing that can kill your metabolism is stress and we all know that a lack of sleep can lead to a more stressful week.