High triglycerides usually come down to one of a few things: too much sugar or refined carbohydrate in your diet, insulin resistance, excess weight, certain medications, or genetics. Often it’s a combination. Your blood test results fall into clear categories: under 150 mg/dL is healthy, 150 to 199 is borderline high, 200 to 499 is high, and 500 or above is very high.
Sugar and Refined Carbs Are the Biggest Dietary Driver
Most people assume dietary fat is the culprit behind high triglycerides, but sugar and refined carbohydrates are far more likely to blame. When you eat fructose (from table sugar, high-fructose corn syrup, fruit juice, or sweetened drinks), nearly all of it goes straight to your liver. There, it’s rapidly converted into fat through a process called de novo lipogenesis, literally “new fat creation.” Unlike glucose, which your whole body uses for energy, fructose is metabolized almost exclusively by the liver and funneled into triglyceride production.
What makes fructose particularly problematic is that this conversion happens fast and without the usual metabolic brakes. The liver enzymes that process fructose work efficiently and with little regulation, so large amounts of incoming fructose translate directly into large amounts of new fat. Over time, regularly consuming fructose actually ramps up the liver’s fat-making machinery, increasing the expression of enzymes involved in fat synthesis. This creates a cycle: the more fructose you eat chronically, the better your liver gets at turning it into triglycerides, and the higher your levels climb.
White bread, pasta, rice, and other refined starches can do the same thing. Your body breaks them down into glucose quickly, and when that glucose floods the liver faster than your muscles can use it, the excess gets converted to triglycerides. Alcohol works through a similar pathway. Even moderate drinking can raise triglyceride levels because the liver prioritizes processing alcohol over other metabolic tasks, and the byproducts feed directly into fat production.
Insulin Resistance and Belly Fat
Insulin resistance is one of the most common metabolic reasons for elevated triglycerides, and it often goes undiagnosed for years. When your cells stop responding normally to insulin, several things go wrong at once. Fat cells become less responsive to insulin’s signal to store fat, so they release more fatty acids into the bloodstream. Those fatty acids travel to the liver, which packages them into triglyceride-rich particles and ships them back out into your blood. At the same time, insulin resistance increases the liver’s own fat production from glucose. All three major sources of liver triglycerides (fatty acids from fat tissue, remnants from digested food, and newly made fat from sugar) are abnormally elevated in people with insulin resistance.
You don’t need a diabetes diagnosis for this to be happening. Insulin resistance is a feature of prediabetes and metabolic syndrome, and it’s closely linked to carrying excess weight around the midsection. If your triglycerides are high alongside a low HDL cholesterol level (under 40 for men, under 50 for women) and an elevated A1c, insulin resistance is very likely part of the picture.
Medications That Raise Triglycerides
Several common medications can push triglyceride levels up, sometimes significantly. If your levels rose after starting a new prescription, the drug itself may be contributing. Known offenders include:
- Corticosteroids like prednisone, often prescribed for inflammation or autoimmune conditions
- Thiazide diuretics, commonly used for blood pressure
- Nonselective beta-blockers, another blood pressure medication class
- Second-generation antipsychotics such as clozapine and olanzapine
- Oral estrogen, including some forms of hormone replacement therapy
- Antiretroviral protease inhibitors used in HIV treatment
- Tamoxifen, used in breast cancer treatment
If you suspect a medication is involved, your doctor can check whether an alternative exists that’s less likely to affect your lipids. Don’t stop any prescription on your own.
Genetics and Family History
Some people have high triglycerides despite eating well and staying active. Familial hypertriglyceridemia is an inherited condition caused by genetic variants that impair how your body processes triglycerides. It tends to cluster in families and is made worse by environmental factors like diet, weight gain, or the medications listed above. If multiple relatives have high triglycerides or you’ve had elevated levels since you were young, genetics is likely playing a role. Genetic causes don’t mean the levels can’t be managed, but they do mean lifestyle changes alone may not be enough.
Why High Triglycerides Matter
Borderline or moderately high triglycerides (150 to 499 mg/dL) increase your long-term risk of heart disease, particularly when paired with low HDL cholesterol or other metabolic syndrome features. The more immediate danger comes at the very high end. Levels above 1,000 mg/dL carry roughly a 10% risk of acute pancreatitis, a painful and potentially life-threatening inflammation of the pancreas. Above 5,000 mg/dL, the risk jumps to over 50%. Below 1,000, pancreatitis from triglycerides alone is unlikely.
Fasting vs. Nonfasting Blood Tests
Triglyceride levels are ideally measured after a 9 to 12 hour fast, since eating can temporarily raise them. But nonfasting results are still clinically useful. The American Heart Association has noted that a nonfasting triglyceride level above 200 mg/dL is enough to flag a problem. If your nonfasting result comes back elevated, your doctor will typically order a repeat fasting test in two to four weeks to confirm. The exception: when levels are extremely high (around 1,000 mg/dL or more), there’s no need to wait for a fasting retest before starting treatment.
What Actually Lowers Triglycerides
The most effective first step is cutting back on added sugars, sweetened beverages, refined carbohydrates, and alcohol. Because fructose is so directly converted to triglycerides in the liver, reducing it can produce noticeable drops in levels within weeks. Replacing refined carbs with fiber-rich whole grains, vegetables, and lean protein shifts the metabolic equation.
Losing excess weight, even a modest amount, improves insulin sensitivity and reduces the flow of fatty acids to the liver. Regular aerobic exercise does the same, independent of weight loss. Even 150 minutes per week of moderate activity (brisk walking counts) can meaningfully lower triglycerides.
Omega-3 fatty acids from fish oil are one of the better-studied interventions. At prescription doses of 4 grams per day, omega-3s reduce triglycerides by roughly 20% to 30% in people with elevated levels. In those already taking a statin, adding high-dose omega-3s still achieved about a 21% reduction. One study in people with very low baseline omega-3 blood levels saw a 48% drop. Over-the-counter fish oil supplements contain much lower doses and produce smaller effects, so the magnitude of benefit depends on the amount consumed and your starting levels.
If lifestyle changes and omega-3s aren’t enough, especially with genetic causes or very high levels, prescription medications may be needed. Your doctor can assess whether your triglycerides are part of a broader metabolic pattern that requires a more aggressive approach.