A respected U.S. heart specialist, Dr. Dmitry Yaranov, is warning adults to take a second look at “diet” or “zero-sugar” drinks. After years treating heart patients, he says these beverages are now something he avoids completely. His message is simple: the words “zero sugar” do not mean a drink is harmless.

Dr. Yaranov points to new research showing that people who drink diet or zero-sugar sodas every day may face a higher risk of liver disease than people who drink regular sugary sodas. According to him, the artificial sweeteners in these drinks seem to disrupt the gut and make it harder for the liver to process fat. The result, he says, is roughly a 60% increase in risk for metabolic liver disease—slightly higher than the risk linked to sugary drinks.

For people aged 45 and older, his message is especially relevant: your liver and heart feel the long-term effects of what you drink every day. And while giving up sugar is important, swapping sugary beverages for diet versions may not offer the protection many expect. His clearest advice is also the simplest—water remains the safest daily drink.

Dr. Yaranov also cautions against assuming that being thin or athletic means being healthy on the inside. He has treated extremely fit adults with serious heart problems caused by years of extreme, high-protein diets that cut out plant foods. These eating patterns, he notes, can raise bad cholesterol, damage blood vessels, and accelerate plaque buildup—problems that matter even more as we age.

His guidance for midlife adults is straightforward: avoid diet sodas, limit extreme diets, pay attention to long-term habits, and choose whole foods and water whenever possible. Small daily choices, he stresses, protect your heart and liver far more than quick fixes or “zero-guilt” labels.