6 Ways Added Sugar Causes Weight Gain

Written by Marixie Ann Obsioma, MT, undergrad MD on October 13, 2021

Sugar is often described as one of the major enemies to our health and wellbeing. We are told not to consume too much-added sugar due to its impact on weight, diabetes risk, and more. But how does sugar cause these problems, specifically weight gain? In this post, we are going to focus on different ways through which sugar can make you put on weight.

Blood Glucose Overview

Blood glucose, also known as blood sugar, is defined as the primary sugar in the blood. Your body makes glucose from the food you eat, and it is carried through the bloodstream. The main function of glucose is to supply cells in our body with much-needed energy so they can do their “job” properly (1).

However, glucose isn’t enough because cells can’t use it without insulin. Levels of blood sugar increase as we eat and at this point the pancreas automatically releases insulin to allow glucose to enter cells. Insulin regulates blood glucose levels and prevents them from getting too high or low. Insulin resistance can impair this balance and cause many problems with high blood glucose.

Blood Glucose and Diabetes

Elevated levels of blood sugar make us susceptible to pre-diabetes and diabetes. Pre-diabetes occurs when blood glucose levels are high but not as high to be considered type 2 diabetes. It’s a pre-diagnosis and a warning sign that tells patients there’s still time to reverse blood glucose and prevent diabetes. On the flip side, diabetes is a lifelong, chronic condition associated with abnormally high levels of blood glucose in the body and it occurs when insulin resistance dramatically increases sugar concentration.

According to the CDC, 34.2 million Americans have diabetes. More precisely, one in 10 people have this lifelong condition. On the flip side, 88 million American adults have prediabetes or one in three people (2).

Diabetes is a major problem on a global level. For comparison sake, the number of people with diabetes jumped from 108 million in 1980 to 422 million in 2014, according to the WHO (3). The International Diabetes Federation reports in 2019 about 463 million adults were living with diabetes worldwide. This number is expected to rise to 700 million by 2045 (4).

Diabetes is a major problem on a national level, not just a global level and it is a public health concern in other countries besides the U.S. Let’s take Malaysia as an example.

Some estimates show that more than 20% of the adult population in Malaysia has pre-diabetes, but diabetes figures are more worrying (5). The chairman of the National Diabetes Institute (NADI) reported that Malaysia has a higher diabetes rate than any other country in Asia. Figures reveal that over 2.5 million people ages 18 and older have diabetes in Malaysia (6). The International Diabetes Foundation (IDF) reports there were 3.4 million cases of diabetes in Malaysia in 2017 (7).

What Happens When the Body Accumulates More Sugar than Needed?

Excess blood glucose can create numerous problems in our body, and it accumulates when insulin doesn't do its job properly. As a result, there's nothing to regulate glucose levels, and they keep increasing because blood sugar can't enter cells on its own, without insulin. Consequences of blood glucose accumulation are numerous ranging from overweight or obesity, difficulty to lose weight, high blood pressure, increased risk of heart disease, and cardiovascular events such as heart attack. It's also important to mention that accumulation of blood glucose leads to "clogging" of the capillaries or tiny blood vessels in your eyes, kidneys, and extremities leading to poor circulation and increased risk of heart conditions affecting these organs and body parts.

Glucose-Insulin Relationship

Insulin is a hormone produced by the pancreas with the goal to allow the body to use sugar or glucose from food for energy (8). As it was already mentioned, insulin is vital for glucose regulation because without this hormone cells can’t take up and utilize blood sugar. Even though there is always a low level of insulin secreted by the pancreas, the concentration of this hormone increases as we eat, i.e., as the blood glucose levels rise. When cells don't respond to insulin properly, levels of blood glucose rise.

This is called insulin resistance, and it occurs due to numerous factors such as for overweight or obesity, chronic stress, high-calorie, high-carb, and high-sugar diet, sedentary lifestyle, polycystic ovary disease, Cushing’s disease, and many others (9). In other words, insulin and glucose are closely tied to one another. The activity of this hormone is vital for the balance of blood sugar.

Storage of Excess Sugar in the Liver

After carbs are absorbed from the food, they are carried to the liver for further processing. In the liver, other forms of sugar are transformed into glucose. Then, one share of glucose is released into the bloodstream while the other remains stored in the liver as energy backs up. In the liver, glucose is phosphorylated to G6P (glucose-6-phosphate) and is further metabolized into glycogen (form in which glucose is stored), fatty acids, and triglycerides for energy purposes. Your liver can only store a certain amount of glucose in the form of glycogen which is why it is also stored in your muscles. Carbohydrates that are stored beyond storage capacity are turned into fat, which explains why we gain weight.

How Does Added Sugar Cause Weight Gain?

As seen above, excess sugar in the blood can cause various problems ranging from weight gain to diabetes and many others (see below). This usually happens due to excessive intake of added sugar. But how does added sugar really lead to excess weight? Several mechanisms are involved and we are going to discuss them below.

1. Empty Calories

The term added sugar refers to sweeteners added to different foods and beverages to improve their taste. Excess sugar can contribute to weight gain due to high-calorie content, but at the same time it doesn’t supply the body with nutrients it can use. That’s why we use the term “empty calories”. Consuming small amounts of added sugars may not cause weight gain, but continued use can. That happens because the constant inflow of empty calories is always higher than the number of calories you burn during the day.

2. Insulin Resistance and Hormone Problems

Eating sugary foods increases blood glucose levels, we’ve already established. When blood glucose levels are elevated for a longer period of time you experience hyperglycemia. This problem causes various complications (see below) including weight gain (10). Hyperglycemia causes weight gain through insulin resistance. You see, high blood sugar levels can disrupt normal cell function and promote inflammation. As a result, insulin resistance happens and the cycle continues. For that reason, insulin resistance can increase body fat, especially in the abdominal area (11, 12). Too much sugar in your blood and subsequent insulin resistance can interfere with leptin. This hormone reduces hunger and food intake. Problems with leptin increase your appetite so you end up eating more added sugar and gain more weight.

3. Foods with Added Sugar Can Cause Overeating

The term overeating refers to food consumption that is inappropriately large compared to energy expenditure. This unhealthy eating behavior leads to obesity (13). How does added sugar lead to overeating, you wonder? Foods with added sugar tend to be low in protein. The body needs this macronutrient to control blood sugar and promote a feeling of fullness by regulating hunger hormones (14). When you eat protein-rich foods you feel full for longer because they can suppress appetite. The same happens with fiber, which also is present in inadequate amounts in foods abundant with added sugar. Without appetite-suppressing compounds, these foods are less filling. As a result, you feel hungry soon after you’ve already eaten. Then, you need to eat more and the cycle continues. You end up eating more food than the body actually needs.

4. Reduced Intake of Healthy Foods

Ideally, we need to focus on a well-balanced diet. Our body requires a wide range of nutrients and micronutrients to function properly. The nutrient profile among food groups differs, so our diet needs to be versatile. The theory is one thing and reality is something else entirely. The truth is that most people consume an unhealthy diet loaded with added sugar. The more added sugar you consume through different products, the lower is your intake of healthy food. In other words, added sugar pushes out healthy foods and takes its place in your diet. Eventually, the greatest portion of your daily menu consists of foods with added sugar and paves the way to weight gain and other problems.

5. Lack of Antioxidants

Antioxidants are compounds that neutralize free radicals and protect us against oxidative stress and damage it would cause. Fruits and vegetables are rich in antioxidants that keep us healthy. On the flip side, foods with added sugar do not supply our bodies with these compounds. Why does that matter? It matters because oxidative stress can lead to weight gain. Evidence shows fat accumulation in the body is closely correlated with markers of oxidative stress. In fact, oxidative stress correlates with BMI (15). The underlying mechanisms of action require further research, but several factors are involved including inflammatory state and reduced expression of antioxidant enzymes.

While a well-balanced diet could improve your antioxidant profile and help neutralize free radicals, a diet rich in abundant sugar fails to do so. As a result, you are more prone to inflammation, weight gain, fat accumulation, and low antioxidant defenses.

6. Added Sugar Affects Mental Health

Everything we eat can either positively or negatively affect our mental health and wellbeing. Our society, however, doesn’t talk much about this subject. Science says we should. Studies show that sugar intake from sweet food or beverages increases the likelihood of incident mood disorders and may contribute to the development of depression (16). Although further research is necessary, studies have found evidence the sugar consumption can directly impact the prevalence of major depression (17). When you take into consideration how the prevalence of both added sugar intake and depression, these findings are not so shocking.

Just like excess weight can increase the risk of depression the vice versa can also happen. Evidence shows women who experienced depressive symptoms had greater increases in BMI, waist circumference, and hip circumference across adulthood (18). In depressed persons, weight gain often correlates with the severity of depression. In one study, subjects with the most severe symptoms of depression also gained more weight (19).

Depression and weight gain may go hand in hand. For example, a high intake of added sugar can be a part of emotional or binge eating. In this case, a person eats a lot of unhealthy added sugar-laden foods not because they’re hungry, but due to sadness, feeling of helplessness, and other negative emotions. Food becomes a coping mechanism in these situations. Since excessive food intake can lead to weight gain, problems with self-esteem arise. This only aggravates the emotional eating problem and contributes to depression. These problems intertwine until a person proactively manages depression and changes diet to slim down. Emotional eating is a part of the bigger problem but it almost always includes a high intake of added sugar or trans fats. Depression is a common reason behind emotional or binge eating and through this relationship, you can gain pounds besides other health problems.

NOTE: Consumption of added sugar leads to various problems, but you are not powerless. Strive to reduce intake of these foods and increase consumption of healthy foods containing protein, fiber, vitamins, minerals, antioxidants, and other compounds. You will have the chance to achieve a healthy weight, especially when you combine a well-balanced diet with regular exercise.

Effects of High Blood Sugar (Hyperglycemia) On Our Body

Hyperglycaemia, or hyperglycemia, is defined as the abnormally high level of glucose in the blood and it is a common occurrence in diabetes (20). You see, diabetes downplays the activity of insulin by affecting the pancreas or making the body resistant to this hormone and it causes spikes in glucose levels. Early signs of hyperglycemia include blurred vision, frequent urination, increased thirst, headache, and fatigue. Hyperglycemia has serious effects on the body including:

Nerve damage: Uncontrolled high blood sugar damages nerves and interferes with their ability to send signals thus causing diabetic neuropathy.
Kidney damage: Hyperglycemia can affect kidneys by damaging blood vessels inside them. This happens because filtering units in kidneys are filled with small blood vessels and high blood sugar narrows and clog them.
Retinal damage: High blood pressure narrows and clogs tiny blood vessels thus increasing the pressure in your eyes. Sometimes these weakened blood vessels leak fluid and blood into the retina.
Atherosclerosis (heart disease, stroke, peripheral artery disease): Hyperglycemia increases inflammation in blood vessels and slows down blood flow. Atherosclerosis or hardening of the arteries is a major risk factor for heart disease, heart attack, stroke, etc.
Slow wound healing: High blood glucose can over time lead to neuropathy and cause poor blood circulation which is vital for wound healing. As a result, it’s difficult for blood to reach affected areas. Since blood is important for wound healing, it’s clear why hyperglycemia slows it down.
High blood pressure: Due to the fact that high blood glucose narrows blood vessels and impairs blood flow, a person with this condition is at a higher risk of developing hypertension or high blood pressure which is also a major risk factor for many cardiovascular problems.

Conclusion

High blood glucose makes you susceptible to the development of prediabetes and diabetes. Throughout this article, you’ve had the opportunity to learn more about the harmful effects of high blood sugar on your health and quality of life. A great way to avoid these complications is to check blood glucose regularly at BioMark even more so if you’re at a higher risk (overweight, sedentary). There’s a lot you can do to keep blood sugar in a normal range.