Question

determine which macronutrient is best described by the scenario in the left - hand column.
important energy
source for low - or
moderate - intensity
aerobic exercise of
more than 20 minutes
for endurance athletes
training, the majority
of calories should
come from this
macronutrient
the most important
macronutrient to
consume during
exercise that
surpasses one hour
contribution of this
macronutrient to
energy needs for
fueling muscles is
generally small
protein
fat
carbohydrate

Explanation:

• Fat is an important energy source for low - or moderate - intensity aerobic exercise of more than 20 minutes. It is a more efficient energy source for long - duration, low - intensity activities as it can be oxidized aerobically.
• Carbohydrate is the most important macronutrient for endurance athletes in training. During exercise, especially prolonged exercise, carbohydrates (in the form of glycogen in muscles and liver) are broken down to glucose, which is used for energy. For exercise that surpasses one hour, carbohydrate intake is crucial to maintain blood glucose levels and glycogen stores.
• Protein's contribution to energy needs for fueling muscles is generally small. Proteins are mainly used for building and repairing tissues, making enzymes, hormones, etc. While in extreme situations (like very low - calorie diets or extremely prolonged exercise with no carbohydrate intake), proteins can be used for energy, but this is not their primary role.

Answer:

1. Fat
2. Carbohydrate
3. Carbohydrate
4. Protein