Can Low Blood Sugar Make You Lose Weight?

Hypoglycemia, or low blood sugar, most commonly occurs among diabetics, people taking certain medications or those with deficiencies of specific hormones and enzymes. But among people who are desperately trying to lose weight, not eating enough food or exercising too much can cause extremely low blood sugar levels. And although these people might believe that low blood sugar is helping them lose weight, it’s actually doing more harm than good.

Someone is testing their blood sugar. (Image: Hunterann/iStock/Getty Images)


The body enters a state of hypoglycemia when blood sugar levels drop below normal. Often referred to as “low blood sugar” or “low blood glucose,” the condition generally occurs once blood glucose levels drop below 70 mg/dL. Carbohydrates, including rice, grains, potatoes, wheat, fruit, milk and sugar, are the body’s main sources of glucose. Once glucose enters the bloodstream, it is transported to the body’s cells where it is used as a source of energy. Excess glucose is stored as either glycogen or fat, both of which can be used as alternative energy sources when necessary.

Since carbohydrates are your body's main source of glucose, eating too little food or not eating often enough can easily result in low blood sugar. Additionally, vigorous exercise increases the amount of insulin produced in your body, which breaks down blood sugar. As a result, too much insulin production often results in low blood sugar levels.

Blood Sugar and Weight Loss

Since excess glucose is stored as fat, some people assume that keeping blood sugar levels low will result in the breakdown of fat when energy is needed. However, if your blood sugar levels remain too low for too long, your body begins to think that starvation is imminent. In response, it goes into survival mode. As part of survival mode, your body stops burning fat and instead protects these important fat cells. At this point, all weight that is lost comes from muscle and your body’s water supply. Although the weight will probably be dropping pretty quickly, it’s an extremely unhealthy form of weight loss that could result in permanent damage to the body. Although it might seem as though your low blood sugar level is helping you lose the weight, it’s actually harming your body.


Early symptoms of hypoglycemia are distracting, although not necessarily dangerous. These early signs might include intense hunger, shakiness, dizziness, sudden sweating and a feeling of nervousness. If your blood glucose levels remain low, symptoms progress to include confusion, anxiety, difficulty speaking, weakness and clumsiness. Severe hypoglycemia that goes untreated could lead to seizures, coma and death.


Although low blood sugar can be extremely dangerous, high blood sugar is just as risky. The condition of hyperglycemia, or high blood sugar, occurs when the body cannot produce enough insulin to process its carbohydrate levels. If you allow blood sugar levels to remain elevated for too long, a condition known as ketoacidosis could occur. When this happens, the body begins breaking down fat to use as fuel. When fat is broken down, ketone waste products are produced. If too many ketones accumulate in the bloodstream, it could result in coma or death.

Safety Recommendations

To ensure your safety while losing weight, speak with your doctor about your body’s safe blood sugar levels. For people without diabetes, blood sugar levels should remain at 70 to 99 mg/dL while fasting or 70 to 140 mg/dL after meals. For people with diabetes, blood sugar levels should remain at 70 to 140 mg/dL while fasting and 70 to 180 mg/dL after meals.

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