McDonald’s and KFC have been ranked among the world’s least healthy fast food chains in a new report that assessed major restaurant brands based on the nutritional quality of their menu items.

The WorldAtlas report, published in July 2025 and highlighted by Yahoo Finance, ranked Wendy’s as the unhealthiest fast food chain, followed by Sonic, Taco Bell, Dairy Queen, KFC, Quiznos, McDonald’s, Smashburger, Little Caesars, and Chick-fil-A.

The rankings were based on factors including calorie content, sodium, saturated fat, and the promotion of oversized meals. Many of the chain’s most popular menu items were found to contain significantly more calories and salt than recommended for a single meal.

For example, Wendy’s Triple Baconator meal with large fries and a medium Frosty contains around 2,160 calories, 54 grams of saturated fat, and 3,400 milligrams of sodium. Similar meal combinations at Sonic and other chains also exceed 1,600 calories and contain extremely high sodium levels.

The report notes that diets high in sodium can increase the risk of high blood pressure, while excessive saturated fat is associated with heart disease. Regular consumption of calorie-dense fast food also contributes to obesity and related chronic illnesses.

Researchers also highlighted the widespread use of ultra-processed ingredients, including refined seed oils, added sugars, preservatives, emulsifiers, and other additives designed to improve taste, texture, and shelf life. These ingredients have become increasingly common in commercially prepared foods over the past several decades.

The report points out that obesity rates have risen sharply since the 1970s as ultra-processed foods became a much larger part of everyday diets. Recent research estimates that such foods now account for about 60% of the average American diet, compared with less than 40% in the 1980s, a shift many experts believe has contributed to rising rates of obesity and other chronic health conditions.