You might know that diabetes is a significant health problem in the United States. Upwards of 37 million U.S. adults—more than 1 in 10 people—have diabetes, according to the Centers for Disease Control and Prevention (CDC).
Type 2 diabetes tends to be associated with being obese or overweight. And these conditions certainly are risk factors for diabetes.
But in reality, there are many other risk factors for developing type 2 diabetes. Body weight is not the only contributing factor. Other common risk factors include:
- Having a close family member with diabetes
- Being 45 years old or older
- Having gestational diabetes (a form of diabetes that happens during pregnancy)
- Giving birth to a baby weighing more than nine pounds
- Being Black, Hispanic or Latino, American Indian, or Alaska Native
- Being physically inactive
People of all body types can develop type 2 diabetes, including people who appear slender and physically active. What’s more, the symptoms for the majority of people affected by type 2 diabetes, regardless of body type, can be quite subtle.
The location of body fat matters
The risk for type 2 diabetes is more about the kind of fat you have inside your body than what is visible on the outside. The type of fat that is particularly dangerous is known as visceral fat. It can lead to inflammation in the body and a range of other health conditions.
Visceral fat lies deep within your body and surrounds your organs, as opposed to the fat that lies just beneath your skin, known as subcutaneous fat.
Some people who look slim on the outside may have unhealthy amounts of visceral fat. This body type is known by a number of names, including:
- Thin-fat phenotype
- TOFI (thin-outside-fat-inside)
- Normal weight obesity
- Hidden obesity
This phenomenon has been studied in depth in tropical countries because it seems to be prevalent in those areas.
A 2022 systematic review published in Frontiers in Endocrinology examined 25 studies and found that normal weight obesity was linked to an increased risk of developing several serious health conditions, including diabetes.
Research has also shown that the risk of dying is much higher in people who have a normal body weight but whose weight is concentrated around their middles. For example, a 2019 review of studies published in Canadian Family Physician drew a direct line between visceral fat and higher mortality risk.
Research specific to diabetes has also suggested links between the location of visceral fat in the body and diabetes risk. For example, a 2022 study published in Frontiers in Physiology found that people with low body mass index (BMI) but higher fat accumulation in the pancreas may be more at risk of developing type 2 diabetes. (BMI is an approximate measure of body fatness that factors in the ratio of one’s weight to height.)
Risk factors for having normal weight obesity
How does one develop the type of body composition associated with normal weight obesity? While research is still ongoing, here are some of the primary drivers:
Low-quality diet
It may be that people considered to have normal weight obesity watch their calorie intake to try to manage their weight, but they don’t eat high-quality, healthful calories.
That may mean having dietary habits like these:
- Skipping breakfast but eating a small bag of potato chips or cookies for lunch
- Eating pasta for dinner and a salad with regular dressing
- Drinking diet soda through the day
You may not gain weight eating in this way, but the intake of refined carbohydrates (from foods like chips, crackers, and pasta) may contribute to an increase in visceral fat.
In particular, added sugars have been found to trigger the release of insulin, a hormone that helps the body manage blood sugar levels. Increased levels of insulin increase the storage of fat. For some people, their body’s storage capacity in subcutaneous fat areas can effectively fill up, which causes the body to switch to storing fat viscerally (deeper inside the belly).
Yo-yo dieting
Another factor that may contribute to developing normal weight obesity is weight cycling, also known as yo-yo dieting. When you lose weight quickly, the body responds to the weight loss by reducing levels of two important functions:
- Energy expenditure: the total amount of energy to body requires to function each day (including moving and working)
- Resting metabolic rate: the amount of energy the body needs to function at rest
Meanwhile, with rapid weight loss, the body increases sensations of hunger. This is a reason why people who’ve lost weight often gain it back again. They then try to lose it again, creating a cycle that makes it difficult to maintain weight loss.
A 2021 systematic review in the Journal of Diabetes Investigation looked at 14 studies and found that people with weight cycling had a 25 percent higher risk for developing diabetes. Researchers are not yet sure of the reasons, but they think that weight cycling disturbs the metabolism and encourages visceral fat to accumulate.
Stress
When a person is constantly stressed, the body goes into “fight or flight” mode to prepare for a dangerous situation. This prompts the body to release cortisol and other stress hormones. It also sets into a motion a metabolic mechanism to store fat, which can provide some quick-burning energy in case of emergency.
What’s more, chronically high levels of cortisol can lead to inflammation and may decrease insulin sensitivity. Over time, poor insulin sensitivity can lead to insulin resistance and a higher risk of developing diabetes
Other possible risk factors
Research that focused on people in South Asia (a region of the world that includes India and Pakistan) has also uncovered other probable risk factors for normal weight obesity. These include genetic predisposition, low birth weight, and maternal malnutrition.
Identifying diabetes signs in people with normal weight obesity
Generally speaking, most patients and healthcare providers (HCPs) are not on the lookout for diabetes in people who appear to be thin or are considered to be of "normal" weight. When it comes to diabetes, it can also be difficult to identify symptoms because many of them are subtle and resemble those of other conditions. These may include the following:
- Excessive thirst or hunger
- Increased urination, especially at night
- Fatigue
- Tingling of the fingers and toes
- Blurred vision
- Frequent colds
- Sores that heal more slowly
- Unintentional weight loss
Because of this relatively “silent” nature of diabetes, it is generally recommended that adults are screened for diabetes on a regular timetable. This may mean having fasting blood sugar or hemoglobin A1C checked every three years starting at age 35 for people with overweight or obesity. If you have other significant risk factors, you may need to get tested earlier and more often.
Treatment for type 2 diabetes
Type 2 diabetes is treatable with diet, exercise, and medications (if need be). Regardless of your risk factors or body type, it is important that you get regular checkups, pay attention to any changes in your body, and report any symptoms to your HCP.
If you are in tune with your body and your well-being, you can increase your chances of picking up on symptoms before you develop prediabetes or full-blown type 2 diabetes.
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