Do Carbs Make You Fat?

Published on December 4, 2019 and last updated for accuracy on December 5, 2019
bagels as an example of carbohydrate

Carbohydrates have an air of mystery surrounding them. During our younger years, we were told to consume foods that are high in carbohydrates to keep us fueled and energized throughout the day. So, many us grew up thinking carbs are good. Our parents told us to chomp down our cereal every morning because it will help us to get things done. Dietary carbohydrates are responsible for controlling energy balance. Food regulation is partially dependent on our carbohydrate needs (1).

Then, we grew up. The rose-colored glass surrounding carbohydrates was shattered. With all the fad diets blaming carbs as the number one reason for weight gain, we can’t help but doubt our beliefs. Over the years, there have been different reports on which type of diet works best and the number of carbs permitted in the body are always of great concern (2). Carbs are now the new “fat”. For years, we have been told that consuming fat can lead to a multitude of chronic diseases. Now, experts agree that carbs are the reason why this happens. It is downright confusing. Do carbs make you fat? Is it not a reliable source of fuel? 

What Happens When We Eat Carbs?

Upon carbohydrate consumption, they get broken down by the body into glucose, also known as the blood sugar. Glucose, like fatty acids, serves as fuel to help us achieve things that we need to do in a day. Blood sugar increases after processing carbs. The pancreas then releases insulin into the bloodstream as a response. The brain uses up around 50 percent of the glucose in the body. Glucose metabolism is very much integrated with how the brain functions (3).

The muscles also benefit from glucose. In fact, one study suggested that starvation can lead to an inhibition of glucose metabolism of the skeletal muscles (4). Without glucose, the muscles will not be able to sustain themselves. It will make activities like running and weightlifting a lot more exhausting and challenging.

Having too much glucose in the bloodstream means that the remaining amount (apart from those used up by the muscles and the brain) will be redirected to the muscle and liver cells. About 500 grams of glycogen (stored glucose) can be stored in our muscles while about only 100 grams can be retained in the liver. Anything in excess will need to be stored somewhere else. Having too much glucose in the bloodstream can bring negative effects to certain cells. The remaining free glucose is converted to triglycerides and stored as fat.

How Did We Start Alienating Carbs?

In the past decade, we have been taught to cut down on carbs. As the primary suspect in the case of obesity, low-carb diets started to gain traction among health enthusiasts. But, guess what? The war on carbs began years before that. As early as 1860, low-carb diets have been considered one of the most ideal strategies to lose weight (3). One of the first believers that carbs are bad is William Banting. He pushed forward a low-carb diet and called it the Banting. It became really popular. 

In the seventies, the Atkins diet also drew in many followers. But, the low-carb diet trend seems to not be enough. In the 2000s, no carb diets started making the rounds in the lifestyle and diet programs of celebrities and fitness gurus. All of them promised wonderful results. You might have heard of Paleo and South Beach diet which many famous personalities claim to be truly effective.

The main idea surrounding these diets is to restrict our overall carbohydrate intake. There is no unanimity on the rules of a low carb diet. These diets allow different levels of carbohydrates, but almost all restrict the consumption of refined carbohydrates such as cookies, cakes, rice, cereals, bread, potatoes, and corn.

How Does Eating Carbs Lead to Weight Gain?

Consuming added sugars like those present in sweetened drinks, sugary cereals, baked goods, and candies, are contributing factors in weight gain and chronic health conditions (5, 6). Hence, low-carb diets have been hailed very effective in losing additional pounds. This simple diet adjustment can help you in your weight loss journey. Here are some ways carbo-loading and added sugars can make you gain weight.

  • Added sugars, mostly sweeteners, are high in empty calories. They lack nutrients like vitamins, minerals, protein, fiber, and fat, which are all essential for different body functions (7). Regularly indulging in foods containing added sugars may cause you to gain excess weight soon. 
  • Foods high in carbs, specifically refined carbs with high amounts of added sugars, are low in protein and fiber. These can negatively impact appetite and feelings of fullness (8, 9, 10, 11). This can lead to an intense need to eat more frequently and unnecessary food cravings.
  • Though enjoying sweet foods occasionally isn’t likely to cause harm to your health, regular consumption of high amounts of added sugars can increase your blood sugar level and promote weight gain by promoting insulin resistance. High blood sugar level and insulin resistance can interfere with leptin, a major energy regulator in the body that affects calorie intake and burning as well as fat storage. Without it, hunger and food intake increase (12). 
  • By simply eating a fewer number of carbohydrates, the number of calories we burn is increased (4). If you eat more carbs, then the results will be the other way around.
  • Restricting carbs can also lower down insulin levels. Insulin is an important hormone that is responsible for the regulation of blood sugar levels and storing energy. Insulin stimulates the production of fats in the cells known as lipogenesis. It also serves as a storage of fat. At the same time, they take the glucose they encounter as they pass through the bloodstream. Glucose is then processed, instead of fat. This is why low-carb diets are deemed effective; they lower insulin levels (13). With a high carb diet, your insulin levels will dramatically increase leading to fat accumulation.
  • Many people argue that the difficult part of the weight loss journey is keeping the weight off. The type of calories that you take in is likely to influence how you can maintain a healthy diet and weight (14). 

What is the Ideal Daily Carb Intake?

There is no definite number because the amount of carbohydrates we should consume depends per person. In fact, the variations are quite great, it is hard to determine how much carbs to consume to get rid of the extra weight effectively. But for reference, a low-carb diet means consumption of no less than 60 grams of carbs in a day (15). The ketogenic diet is one of the lowest carbohydrate diets. It only allows up to 50 grams of carbohydrates in the body. 

Other low-carb diets are more generous with the carb limit. Try doing a low-carb diet to lose weight by consuming 100 to 125 grams of carbohydrates. Some of the signs that can determine we have found the appropriate carbohydrate allotment are:

  • Increased energy level
  • Decreased appetite
  • Stable blood pressure
  • Steady sugar levels
  • Weight loss

When calorie counting your carbohydrates, consider the fiber content of each. For instance, calorie-rich foods like beans are also rich in fiber. This means upon consumption, they do not have as much negative impact as refined carbs.

A moderate intake of 50% carbohydrate is found in Western cultures, namely in Europe and North America. This is considered low in Asian countries, where the average diet is made of 60% of carbohydrates (16).

What are the Good and Bad Carbohydrates?

Well, here comes a surprise. There is no such thing as good and bad carbohydrates. You can find several things online that discuss which food to consume and which ones to avoid. There are certain foods that contain more nutrients. That is true. We just need to make smart choices. Almost all foods contain the three macronutrients – fat, protein, and carbohydrates. Each one has something beneficial to offer the body. So, it will be hard to find foods that are completely void of carbohydrates. 

Of course, consuming highly processed foods with their preservatives and unnatural ingredients are considered unhealthy. If you want to live a healthy lifestyle, removing foods that have low nutritional value is one of the first steps.

Benefits of Including Carbohydrates in Your Diet 

Carbs are not the enemy. Below are some reasons why the inclusion of this macronutrient in your diet is a good idea.

1. Helps in Controlling Weight

It is recommended to get 14 grams of fiber in every thousand calories consumed. Almost all fiber-rich foods are carbohydrates. Skipping carbs altogether can be unhealthy. Eating foods rich in fiber can make you feel full longer. Luckily, many high-fiber foods have low calories. Foods that contain complex carbohydrates aid in reducing the odds of developing heart disease, cancer, and diabetes (17).

2. Aids in Digestion

Constipation, bloating, and indigestion, are typical digestive issues almost all of us experience regularly. A specific type of fiber is difficult to break down by means of digestion. It is called insoluble fiber. Insoluble fiber speeds up the processes involved by bulking up the stool and pushing the food through the digestive tract. This fiber found in carbs can accelerate the transit of food in the colon and improve the amount of stool and its consistency (18).

3. Supplies the Body With Energy

When you don’t have enough carbohydrates in your body, you feel weak and unfocused. Consuming high-quality carbohydrates is still ideal for high-performance in adults. Protein and dietary fat are able to provide energy, but carbohydrates are still the only macronutrient that gets broken down fast enough to supply the body with energy when doing high-intensity workouts (19).

4. Increases Lifespan If Consumed Moderately

Those who consume high carbohydrates and low carbohydrates seem to have the same life expectancy. What matters most is the quality of food that we consume, be it carbohydrates, fats, or proteins. Too little and too many carbohydrates are considered harmful according to the study (16).

Are Carbs Really the Cause of Weight Gain?

With many conflicting data, it is hard to put the blame on just one contributing factor. Weight gain is multi-faceted in nature, so carbohydrates intake surely is not the only culprit. Carbs turn into fat when there is an excess, so it is so easy to think of carbs as the cause of weight gain. However, one study has proved that carbs do not cause weight gain by themselves (20).

Sixteen obese men, who were given a diet with 50% of carbohydrates, 35% fat, and 15% of protein were observed for four weeks. The menu provided contains foods that are considered typical of the American diet. After those four weeks, they were given a low carb, keto diet which consists of 80% fat, 15% protein, and only 5% carbohydrates for the next four weeks. It has the same number of calories as the former diet. If the carb-insulin-fat hypothesis is true, then participants would have gained weight during the first four weeks, right?

The average amount of fat lost by participants is 1.1 pounds in their four-week keto diet. In the four weeks of high carb diet, the participants also lost the same amount on average. The main difference is that with a keto diet, they experience a decrease in insulin levels, but during the high-carb diet, the insulin levels rose. It seems to prove that while carbs cause a spike in insulin levels, it did not make the participants fatter.

How to Consume Carbs Moderately?

As stated earlier, there is no need to go the extra mile and consume low amounts of carbohydrates. Moderation is the key. Here are some tips to watch the number of carbs you take ensuring a healthy way of life.

1. Say Goodbye to Sugary Drinks

Empty calories and added sugar can lead to type 2 diabetes and obesity. One 12 ounce of sugar soda has 38 grams of carbohydrates (21).

2. No More Frequent Trips to the Bakery

Most people turn to bread for instant hunger buster. However, they are low in fiber despite containing high amounts of carbs. Those that are made with refined grains can lead to weight and health issues (22).

3. Be Mindful of Your Snacking Behavior

Chips and crackers are easy-to-grab snacks. They are perfect to munch on while studying or working. However, having a high-protein snack will help us feel fuller for longer periods of time (23).

4. Eat More Healthy and Non-Starchy Vegetables

Selecting non-starchy foods will help reduce your carb intake. Low-carb and delicious healthy vegetables such as bell peppers, broccoli, and asparagus are good additions to your diet.

Take-Home Message

Increasing hunger and interfering with your hormones are just a few of the reasons why added refined carbohydrates can cause you to gain weight and significantly increase your risk of chronic conditions, including obesity. 

Watching what you eat instead of fixating on one macronutrient may be the best way to have a nourishing diet. Focusing on quality over quantity is one of the best ways to stay healthy and strong in mind and body. Also, try out the simple tips listed above to help kick your bad sugar habit for good. 




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