What is a common nutritional guideline for McDonald's menu items?

The presence of calorie counts on the menu is a common nutritional guideline for McDonald's menu items because it provides customers with essential information to make informed food choices. Displaying calorie counts helps highlight the caloric content of each item, allowing patrons to consider their dietary needs or restrictions when selecting meals. This transparency aligns with broader trends in the food industry toward offering more nutritional information to help consumers make healthier decisions.

While the other options also pertain to nutritional considerations, they do not reflect the standard practice that is universally observed across McDonald's locations. While some locations may offer low sodium options, vegan items, or gluten-free meals, the consistent presence of calorie counts on the menu stands out as a widely implemented guideline across all restaurants.