12 Foods That Slow Down Metabolism

There is a close relationship between body weight and metabolism. In simple words, metabolism is the rate at which your body converts food to energy.

So the faster your metabolism is, the more calories you are burning. Inversely, if your body is not burning calories at a sufficient rate, the food you are eating is not being efficiently used for energy and this can result in excess pounds piling on.

Your metabolism naturally slows down with age, but there are times when a slow metabolism could be attributed to wrong choices of food.

If you are trying to lose those last few excess pounds, ditch these foods to achieve your weight loss goals, and feel great. 

1. Orange and Other Fruit Juices

Fresh fruit juices seem like a safe bet while trying to lose weight. In fact, a glass of orange juice has always been considered a healthy addition to wholesome breakfast. But we forget to keep in mind the sugar content in that refreshing glass of orange juice, especially if it is the packaged version. 

In comparison to a bowl of fresh-cut fruit, juices have a much higher concentration of sugar and are also devoid of the benefits that the fiber in fresh fruit has to offer.

When we consume high doses of such juices, it elevates our blood sugar which, in turn, leads to an insulin spike. This slows down the rate at which we burn calories (1) and the food we eat tends to get stored as fat in our body rather than get used up as fuel (2).

Summary: Fruit juices contain a high concentration of sugar that can cause metabolic diseases. It is best to enjoy the benefits of the fruit in its natural form instead.

2. Granola Bars

Granola and granola bars have found a name as a “healthy” snack. But when we delve a little deeper into what goes into the making of a granola bar, it might surprise you that a regular granola bar has a shocking amount of sugar and some may even have high fructose corn syrup and added preservatives. 

While it is true that they might pack in a substantial amount of fiber because of their oat base, the high sugar could actually be slowing down your metabolism and may be responsible for the pounds piling on.

Granola bars often have dry fruits and nuts and are very high in calories. It is easy to go overboard while munching on one that you picked from the “healthy foods” aisle of your supermarket without giving much thought.

To avoid these extra additives and sugar, it is best to opt for whole-grain bars or better yet, make your own and be in control of what goes into your healthy energy bars. 

Summary: Granola and granola bars might be sneakily slipping in excess sugar into your body and slowing down your metabolism. Opt for whole-grain bars with no added sugar instead.

3. White Bread

When trying to lose weight, one of the first things to get knocked off our diet is white bread, all kinds of white pasta and pizzas; and rightly so. Refined flours used to make these go through a lot of processing and have been stripped off of fiber and hence are called simple carbs.

The body doesn’t need to work too hard to break down these simple carbs. Since simple carbs digest quickly, they often result in blood sugar spikes. Studies show that people who consume more refined grains tend to be at risk of developing insulin resistance and metabolic syndrome (3).

On the other hand, consuming whole grains instead has been associated with many health benefits in regards to resting metabolic rate and weight loss. 

A study was conducted by the University of Minnesota, where 81 men and postmenopausal women were randomly assigned to one of two diets to maintain their weight – one with whole grains and the other with refined grains.

The group consuming whole grains showed a significantly higher resting metabolism than the group consuming refined grains (4).

When you feel like treating yourself to a high-carb meal during your weight loss journey, choose a whole grain option like whole-wheat pasta, brown rice, or a sandwich with whole-grain bread.

Summary: Refined grains and flours are simple carbs and the body breaks it down easily resulting in a low metabolism and blood sugar spikes. Opt for whole grains to increase your metabolism.

4. Regular Sea Salt

Sea salt is derived naturally and contains various minerals but it does not contain iodine. Choosing to use sea salt in your kitchen can put you at risk for iodine deficiency especially if you are a vegetarian and cannot get iodine from other sources like seafood (5).

Iodine is an essential mineral that is used by your thyroid gland to produce thyroid hormones that play a crucial role in your body’s metabolism.

When your body is not getting enough iodine, it affects your thyroid function and in turn your body’s ability to burn calories (6).

Summary: Regular sea salt does not contain iodine which is crucial for your body’s thyroid to function properly. Opt for iodized salt when cooking to ensure your body’s iodine requirement is met.

5. Apples

We’ve been told that apples will keep the doctors away but in reality, conventionally grown apples are covered in pesticide which might be actually doing more harm than good to us.

According to studies, most fruits and vegetables we eat contain harmful pesticides which may be causing our metabolism to dip (7).

Another study conducted in Canada showed that people with a high level of a particular type of pesticide called organochlorines exhibited a lower metabolic rate and also had difficulty losing weight (8).

A Chinese study showed that pregnant women who recorded having high levels of pesticides in their blood ended up giving birth to low birth weight infants (9). This could be because pesticides can cause metabolic dysfunction.

Organic foods are the healthier alternative to conventionally grown produce and it is best to stick to them. Washing and peeling conventional produce before consumption can reduce the risks involved slightly and may reduce your chance of slowing down metabolism.

Summary: Consuming fruits contaminated with pesticides could be slowing down your metabolism. Organic products that are free from pesticides are the best alternative.

6. Sodas with High-Fructose Corn Syrup

A cool summer drink can be incredibly refreshing but have you paid attention to what is in your soda or iced tea? 

The main culprit when it comes to these drinks is fructose and almost 55% of these drinks are made up of high-fructose corn syrup. In fact, 50% of table sugar is fructose. Both of these are highly detrimental to your health.

What’s worse is that it is unbelievably easy to underestimate the amount of fructose in your drink but our body is subject to the damage that follows.

Studies show that high consumption of sugary drinks can lead to diabetes, insulin resistance, and obesity (10).

A 10-week study conducted among obese men who were consuming 25% of their daily calories in the form of sugar-sweetened beverages, showed that they suffered a significant drop in their metabolic rate (11).

In addition, studies also confirm that high fructose consumption lowers physical activity and increases fat deposits in the belly and liver. It is not suitable for those trying to lose weight (12).

Consider switching to water as your preferred choice of beverage at all times.

Summary: Soda contains large amounts of fructose, reduces your metabolic rate, and can also be counterproductive to your weight loss efforts.

7. Drinking Water With Fluoride/Chlorine

Staying hydrated by drinking enough water is crucial to keep your body’s metabolism chugging along. In fact, if you’re experiencing a slow metabolism, increasing your water intake might be one of the first and easiest steps to boost your body’s metabolism (13).

Even so, it is essential to take a close look at the type of water you are drinking. Fluoride and chlorine are a few chemicals that are used to treat water. Both these chemicals used in treated water supplies can cause disruptions in normal thyroid function (14).

When your thyroid is inactive and slow, your metabolism also experiences a slowdown and can sometimes even become dysfunctional (15). Drinking filtered water can be your best bet to keep your metabolism up and avoid any interference with thyroid function.

Summary: Sufficient intake of water is important to avoid the slowing down of your metabolism. However, stay away from drinking chemically treated water especially water that is treated with fluorides and chlorine which negatively affect your thyroid function and slow down your metabolism.

8. Refined Oils with Omega-6 

Another food group that is usually shunned while trying to lose weight is fats. Eating too much fat is definitely not advisable not only for weight loss but also for your heart health. 

In particular, refined oils like sunflower and soybean oil are full of omega-6 fats, which are known to cause inflammation and may also contribute to weight gain (16). 

Omega-6 fatty acids in these oils can also increase insulin resistance and resistance to a hormone called leptin that tells your body when you’re full (17).

A study conducted on mice showed that reducing the amount of omega-6 fats and increasing omega-3 fats instead, increased the metabolism of these mice (18).

It is not necessary to completely ban an entire food group but switching to smarter variants instead, like oils with omega-3 fats, can help you enjoy fats and at the same time not risk lowering your metabolism. Canola and flaxseed oil are a few options for such oils.

Summary: Foods high in omega-6 fats can lower your metabolism by increasing insulin resistance and leptin resistance.

9. Too Much Alcohol

Alcohol consumption can be tricky because there are so many variables to determine the extent of its effect. Age, the type of alcohol, exercise, and other lifestyle habits play a crucial role to gauge the effect it can have on different people.

We might be quick to link alcohol with weight gain because of the high number of calories it contains. But studies have also shown that too much alcohol intake in one sitting can mess up our metabolic processes (19). 

A Melbourne study conducted among elderly men showed that those who consumed more than 5 drinks every day had a higher BMI and fat percentage (20).

In heavy drinkers, alcohol metabolism can cause increased appetite. In addition to that, a lot of the energy that is generated by breaking down the alcohol is wasted and not useful for the body (21).

The best way to enjoy that glass of wine and not allow the body to be subject to the ill effects is to limit our intake to 1 or 2 glasses a day and also switch to a healthy lifestyle of exercise and whole foods (22). 

Summary: Excessive alcohol consumption is detrimental to your health. It can cause increased calorie intake and put you at an increased risk of obesity.

10. Low-Calorie Diets

The first thing we do when trying to lose weight is to start eating less. Eating in a calorie deficit is foundational but when it comes to weight loss but when the deficit becomes extreme, this can backfire.

When you dramatically reduce your food intake, your body begins to burn fewer calories to save up in case of starvation. So the weight might come off easily in the beginning but eventually, you will begin to regain the weight which renders your efforts counterproductive.

A study conducted among overweight women who were consuming 420 calories per day for a period of 4 to 6 months showed that they lost weight at a steady rate but their resting metabolic rate also slowed down significantly. Even after increasing their calorie consumption, their metabolic rate remained much lower than it was before the study (23).

A Japanese study among 32 participants where half of them were asked to consume 1462 calories per day and the other half were asked to consume 1114 calories showed that the resting metabolic rate of the first group dropped by 6% and that of the second group dropped by 13% which is more than double the reduction (24).

You can start with a marginal calorie reduction added with daily workouts to prevent your body’s metabolism from slowing down.

Summary: Very-low-calorie diets over long periods of time can drastically slow down your metabolism and prevent you from losing weight.

11. Insufficient Protein Intake

Protein is extremely helpful in keeping you full and can improve the rate at which you burn calories significantly (25).

Every food requires energy to get digested, absorbed, and get disposed of, and this differs based on its composition. This extra energy needed is called the thermic effect of food.

Researchers have found that protein has a higher thermic effect than carbohydrates or fats. Eating a high-protein diet improves the metabolic rate by 20-30% as compared to only 10-15% for carbs. The metabolic increase after consuming fat is less than 3% (26).

Our body’s metabolic rate certainly slows down when we transition from weight loss to weight maintenance. But increasing protein intake significantly brings down this reduction.

A 2012 study found that amongst participants who were made to follow one of three diets to maintain a 10-15% weight loss, those who ate a high protein and low carbohydrate diet recorded the lowest drop in their resting metabolic rate. Their daily energy expenditure reduced by only 97 calories compared to 297–423 calories in those consumed less protein (27).

Summary: Since protein has a high thermic effect, eating a diet with sufficient protein can keep you feeling full and also prevent your metabolism from slowing down, especially during the maintenance phase of weight loss.

12. Eating Too Much Fat

Eating fat to lose weight is now trending and although it might be achieving quick results for some people, we need to pay attention to the long-term damage it might be causing.

According to researchers at Virginia Tech, eating too much fat may change the way your body processes nutrients. 12 men were asked to follow either a standard diet or a diet high in saturated fat for a period of five days. Changes to insulin sensitivity were measured though muscle biopsies.

They found that those who followed the high-fat diet exhibited a three-fold increase in their endotoxin levels within one hour after their meal and they also lost some ability to metabolize glucose. The ability of our muscles to metabolize glucose is crucial to insulin sensitivity, metabolism, and even risk of diabetes (28).

Summary: Eating too much fat can negatively alter the way your body metabolizes glucose and can put you at risk of diabetes and other metabolic disorders.

The Final Note

Our health is a culmination of the several choices we make every day when it comes to the food we eat. You may be doing all the right things in terms of exercise, sleep, and leading a stress-free life and yet not arrive at your weight loss goals because of a few bad food choices that have led to a slower metabolism. 

It is crucial for our metabolism to be running well for our overall health and well being. 

The good news is that most of these mistakes are easily rectifiable and as long as you are committed to making these right choices a part of your life, your health goals are well within reach.

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