Understanding Diabetes: Dr. Jonathan Liu Explains Types, Symptoms and Risk Factors
Diabetes affects millions of Americans, yet the earliest warning signs are often the easiest to overlook. Fatigue, subtle vision changes or seemingly unrelated family history can all be pieces of a larger picture. And while your annual bloodwork may include a glucose check, it doesn't always tell the full story. Understanding which tests to ask for, and when, can make all the difference.
Dr. Jonathan Liu, board-certified family medicine physician with CaroMont Family Medicine in Lake Wylie, explains the different types of diabetes, and why Type 2 diabetes can often go unnoticed. This knowledge can help you recognize when it's time to talk to a doctor, sometimes long before a diagnosis occurs.
What Is Diabetes?
"Diabetes is a chronic condition that affects how the body turns food into energy,” explains Dr. Liu. “Normally, the body breaks down food into blood sugar and releases insulin, a hormone that helps the sugar enter cells for fuel. With diabetes, the body either doesn't produce enough insulin, cannot use it effectively or both, causing blood sugar to build up in the bloodstream.”
Left unchecked, high blood sugar can quietly affect nearly every part of the body, from the heart and kidneys to the eyes and nerves. Catching diabetes, or prediabetes, sooner gives you more options to manage it and protect your long-term health.
Type 1 vs. Type 2: Understanding the Difference
Though they share a name, Type 1 and Type 2 diabetes are fundamentally different conditions with different causes, onset patterns and treatment approaches. Dr. Liu explains:
Type 1 diabetes is an autoimmune condition where the immune system mistakenly attacks insulin-producing cells in the pancreas. This leaves the body unable to produce insulin. It typically develops in childhood or young adulthood, though it can occur at any age, and it is not linked to weight, diet or physical activity. Because Type 1 cannot be prevented, those diagnosed require lifelong insulin therapy to manage blood sugar.
Type 2 diabetes develops when the body becomes resistant to insulin or fails to produce enough to maintain normal blood sugar levels. It is far more common than Type 1 and is closely tied to factors such as excess weight, physical inactivity, family history and age, though genetics and other health conditions can also play a role. Type 2 typically develops gradually over several years, but lifestyle changes, medication or a combination of both can often help prevent or manage it.
"One of the clearest distinctions between the two is the speed of onset. Type 1 symptoms typically appear suddenly and severely, often over the course of days or weeks. Type 2 symptoms tend to develop slowly and subtly, if they appear at all. This lack of clear warning signs for Type 2 diabetes is why routine screening is critical for early detection," adds Dr. Liu.
The Type 2 Warning Signs Most People Miss
Roughly one in three American adults has prediabetes, and up to 80 percent of them are unaware of their condition. This gap between diagnosis and awareness is where much of the danger lies, as prediabetes and Type 2 diabetes rarely produce clear symptoms. By the time warning signs do appear, they're often easy to write off. Fatigue gets blamed on a busy schedule. Blurry vision gets chalked up to aging eyes. Tingling in the feet gets attributed to sitting too long or wearing the wrong shoes. Increased thirst or more frequent trips to the bathroom might not raise concern at all. Individually, these signs seem minor, but together they can indicate that blood sugar levels have been elevated for some time.
"Prediabetes means blood sugar levels are higher than normal but not high enough to be classified as diabetes," explains Dr. Liu. "While the condition is often reversible, if left unaddressed it frequently leads to Type 2 diabetes. This chronic disease affects how the body regulates blood sugar, which can cause serious complications involving the heart, kidneys, eyes and nerves over time."
One sign people often overlook is darkened, velvety patches of skin, usually around the neck or underarms. It's a lesser-known indicator, but it's one of the few visible clues prediabetes can leave behind. For most people, though, there are no warning signs at all, which is exactly why screening matters.
Why Family History Matters More Than Many Realize
"A parent or sibling with Type 2 diabetes roughly doubles a person's risk of developing the condition," explains Dr. Liu. "That doesn't mean diabetes is inevitable, but it does mean earlier and more frequent screening may be worthwhile, even before standard age-based guidelines would otherwise recommend. Lifestyle changes, including diet, physical activity and weight management, can offset genetic risk, but these interventions are most effective when started before blood sugar problems take hold."
Risk Factors That Don't Get Enough Attention
Some contributors to diabetes risk are less commonly discussed but still significant. Chronic stress and poor sleep can affect insulin sensitivity over time, while certain medications, including some steroids, can raise blood sugar levels. Conditions such as polycystic ovary syndrome and a personal history of gestational diabetes also increase long-term risk, even years after a pregnancy has ended.
Questions Patients Often Ask
Here are the top three questions Dr. Liu receives on diabetes:
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Can I have diabetes and not know it? Yes. Type 2 diabetes and prediabetes often develop with no noticeable symptoms, which is why routine screening matters, especially for those with risk factors.
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Does eating sugar directly cause diabetes? Not on its own. Diabetes risk is shaped by a combination of genetics, weight, activity level and overall diet, not just sugar intake alone.
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If my parent has diabetes, will I get it too? Not necessarily, but the risk is higher. Earlier screening and proactive lifestyle choices can make a meaningful difference.
Taking the Next Step
The most effective step anyone can take is talking to a health care provider about personal risk factors and appropriate screening timing, particularly for those with a family history or other known risk indicators. Diabetes and prediabetes are manageable, and in many cases, preventable, when caught early.
If you have concerns about your risk for diabetes, or if you are searching for a compassionate medical team, our primary care providers are here to help. Find an expert near you that focuses on you and your long-term health.