Question

glucose. ten 25 - year - old healthy male subjects are selected. at 8:00 am every day for 3 days, the test subjects eat a meal based on the chart below.

day	time	meal
1	8:00 am	high fat meal
2	8:00 am	high protein meal
3	8:00 am	high sugar meal

one hour after each meal, the men have their blood insulin levels measured. which of the following is the question the researcher is trying to answer?
how do males process insulin?
how does age affect blood insulin levels?
how does the time of day affect blood insulin levels?
how do different types of food affect blood insulin levels?

Explanation:

The study has subjects eat different types of meals (high - fat, high - protein, high - sugar) and then measures blood insulin levels. The variables being manipulated are the types of food, while other factors like age (all 25 - year - olds), time of day (8:00 am), and gender (males) are controlled.

Answer:

How do different types of food affect blood insulin levels?