Which of the following methods is least likely to affect the healthfulness of a meal?

Using minimal added fats is indeed the method least likely to affect the healthfulness of a meal. This approach emphasizes incorporating healthy cooking techniques while reducing excess calories and unhealthy fat intake. Utilizing minimal added fats promotes the natural flavors of ingredients and can enhance the meal's nutrient profile without significantly detracting from healthfulness.

In contrast, the other methods listed can lead to meals that are less healthy. Frying at high temperatures typically increases the fat content and can create harmful compounds, such as acrylamides, which may pose health risks. Cooking with added sugars can contribute to excessive calorie intake and promote conditions such as obesity and diabetes. Preparing with processed sauces can introduce unhealthy additives, such as high levels of sodium, sugars, or unhealthy fats, which can diminish the nutritional value of the meal.

By focusing on minimal added fats, one can ensure a meal retains its healthful qualities while promoting better dietary habits.