Although your body needs sugar for energy, especially crucial for cells like those in the brain, consuming too much can harm your health. A diet that’s out of balance with too much sugar can contribute to serious health conditions such as diabetes, cognitive problems, and heart disease. Additionally, too much sugar can increase your risk of complications from cancer treatment. It’s important to maintain a healthy balance in your sugar intake to support your well-being and reduce potential health risks.

Importantly, no research suggests that limiting your sugar intake is a viable alternative to appropriate cancer treatment. The best way to improve your chances of a positive outcome with lung cancer is to stick with your treatment plan.

In this article, we’ll discuss how sugar may play a role in lung cancer and whether you should limit it in your diet.

1. Some Types of Cancer Cells Rely on Glucose To Grow

Glucose — the simplest form of sugar — is the fuel for every cell in your body. It enters your cells through a protein called glucose transporter 1 (GLUT1). Cancer cells grow faster than normal cells and need more energy to sustain their rapid growth. To meet this demand, many cancers make more GLUT1 to take up more glucose. This glucose is then broken into smaller molecules to generate energy through a process called glycolysis.

Recent studies have shown that squamous lung carcinoma cells have too many GLUT1 transporters, making them rely heavily on glucose to meet their energy needs. This makes them vulnerable to therapies that target glycolysis.

2. Not All Lung Cancers Depend on Sugar

Lung cancer is the second most common type of cancer in the world. It is broadly classified into two main types: non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC).

NSCLC is more common, accounting for 80 percent to 85 percent of all lung cancer cases in the United States. NSCLC can be further broken down into several groups, but the three most common types are:

• Adenocarcinoma
• Squamous cell carcinoma (SCC)
• Large cell carcinoma

Researchers have found that GLUT1 is specifically more active in squamous cell lung cancer than in lung adenocarcinoma. In laboratory experiments on lung cancer, blocking the GLUT1 protein stopped the growth of SCC cells but not adenocarcinoma cells. These studies indicate that a certain type of lung cancer called lung SCC relies more heavily on sugar for its growth. As a result, there is potential for new treatments that specifically target a protein called GLUT1, which is involved in sugar transport. These treatments could offer hope for improving the management of this type of lung cancer.

Interestingly, GLUT1 protein levels are also higher in other squamous cell cancers, such as those affecting the head, neck, and esophagus. This finding further supports the idea that SCCs may be addicted to sugar.

3. Too Much Sugar Is Associated With Higher Risk for Lung Cancer

Eating too much sugar may raise your risk of lung cancer. High sugar consumption can cause hyperglycemia (high blood sugar levels). Hyperglycemia damages your organs and tissues and is more strongly linked to SCC than to other lung cancer types.

A high-sugar diet also increases your risk of developing diabetes, another major risk factor for developing lung cancer. A sugar-rich diet can also mean eating more calories than needed, which could raise your body mass index (BMI). A higher BMI is associated with an increased risk for lung cancer, especially SCC.

It’s important to note that sugar, on its own, does not cause cancer.

4. High Sugar Consumption May Lead to Poor Prognosis for Lung Cancer

SCCs rely a lot on sugar because they produce higher levels of a glucose transporter called GLUT1. Studies have shown that people with SCC tumors with high levels of GLUT1 have a poor prognosis (outlook). In fact, researchers have found that people with high-GLUT1 tumors have a much lower chance of surviving for five years, especially in people with SCC.

Cancer needs sugar from your blood to grow. Numerous studies have reported worse outcomes for people with NSCLC and high blood glucose. Another study found that people with NSCLC and high blood glucose had faster tumor progression and liver metastases compared to people with NSCLC and normal blood glucose. This makes high blood glucose a prognostic marker for NSCLC, meaning it can be used to predict how well people with NSCLC will do.

People with diabetes are more likely to develop lung cancer. It is also associated with worse outcomes and higher death rates for people with NSCLC. Scientists have not seen this association in people with SCLC. The reason that hyperglycemia and diabetes may contribute to a poor prognosis in lung cancer is not fully understood. However, one possible explanation is that both of these conditions can increase inflammation in your body.

5. A Sugar-Restricted Diet May Help Treat Lung Cancer

Several studies have linked sugar consumption to cancer development. Fast-growing cancer cells need extra glucose for fuel. You can better control your blood glucose levels with a healthy diet. However, you can’t completely give up sugar, as this can also harm your healthy cells.

Some studies in people with cancer have shown that calorie-limiting diets (reducing your calorie intake) or fasting-mimicking diets (a diet involving intermittent fasting) make cancer cells more sensitive to treatment. These diets have also been shown to prevent unwanted side effects from anti-cancer therapies, such as nausea, weakness, or weight loss. (Notably, these diets aren’t limited only to restricting sugar.)

Be sure to talk to your doctor before making any significant changes to your diet.

6. Cancer Cells Use Other Sources of Energy When Glucose Is Low

Cutting out sugar may seem to be a promising treatment for treating sugar-dependent cancers, but it likely won’t work. If your body doesn’t have enough glucose to fuel your cancer cells, they can find other energy sources. This means that limiting sugar might not help treat lung cancer.

Research has found that certain kinds of NSCLC tumors can change how they get energy when there isn't enough sugar around. Instead of relying on sugar, they use a different source called glutamine. They do this by making a special enzyme that turns glutamine into energy, helping them survive even when sugar is scarce. This ability means they don’t need as much sugar to grow. Although this adaptability makes these cancers dangerous, it also makes them open to treatments that focus on their energy sources.

7. Limiting Sugar Can Have Other Health Benefits

More research is needed to determine how a reduced-sugar diet affects lung cancer treatment. Even so, reducing sugar can have benefits.

Your body needs carbohydrates, but eating too much sugar can raise your blood sugar and increase your lung cancer risk. It’s best to eat foods that help you maintain healthy body weight and blood sugar levels.

When choosing carbohydrates, focus on those with a low glycemic index — that is, foods that help release glucose into the bloodstream slowly, which can help prevent spikes in blood sugar. Low-glycemic-index foods include:

• Most fruits and vegetables
• Legumes (e.g., beans and peas)
• Nuts
• Products with minimally processed grains (such as steel-cut oats and whole wheat bread)
• Low-fat dairy foods

Foods that have a high glycemic index, like white bread and sugary baked goods, lead to consistently high blood glucose levels. Research has shown a connection between these types of foods and the increased risk of developing various types of cancer, including SCC.

Talk With Others Who Understand

On MyLungCancerTeam, the social support network for people with lung cancer and their loved ones, more than 10,000 members come together to ask questions, give advice, and share their stories with others who understand.

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