While specific rankings can vary depending on the criteria used (such as nutrient density, prevalence of whole foods, levels of processed foods, etc.), typically, countries that are known for having unhealthy diets may not be found in the top three healthiest diets.
Countries that are often cited as having less healthy diets include those with high consumption of processed foods, sugars, and unhealthy fats. Based on general trends, you would likely find countries such as the United States, United Kingdom, or nations with high levels of fast food consumption and low intake of fruits and vegetables not being in the top three for healthiest diets.
In contrast, countries like Japan, Italy, and Spain are often recognized for their healthy diets, largely due to their emphasis on whole foods, balanced meals, and traditional food practices.