Final answer:
Skim milk has the fewest calories while still containing similar levels of naturally occurring sugars (lactose) compared to whole milk, making it the best option for fewer calories without sacrificing sugar content.
Step-by-step explanation:
If you're looking for a type of milk that has the fewest calories and contains naturally occurring sugars, you'll want to consider the options listed. Among skim milk, whole milk, almond milk, and coconut milk, skim milk generally has the fewest calories while still containing the similar levels of naturally occurring sugars as whole milk, which is lactose. Almond milk and coconut milk usually have fewer calories than cow's milk, but they do not naturally have lactose. They may have added sugars or sweeteners though, which is something to consider regarding calorie content.
Lactose is the sugar found in the milk of humans and cows, and while skim milk has less fat, it still contains roughly the same amount of lactose as whole milk. If you're looking at cow's milk options, skim milk is likely your best choice for fewer calories without sacrificing the nutrient content of naturally occurring sugar, calcium, and often, vitamin D.