It is important to make sure to nourish your body with nutritious food before and after a workout. Eating plenty of fruits and vegetables is important to give your body the nutrients it needs. Without energy, you will feel tired while exercising, and you want to help your body work hard.
You should eat food preferably within a half hour of finishing your workout in order to replenish the energy in your muscles. Without the proper nutrients to refuel your muscles, your body could start using muscle for energy instead of food.
In all of your meals, make sure to include a healthy balance of protein, carbohydrates and fats, because all three are used as important fuel in your body. Make sure to eat lots of fruits and vegetables, as these provide your body with fiber, vitamins and minerals necessary to help your body function correctly.
Now, try this workout.
4 Rounds for Time: (modifications in parentheses)
5 pushups (can be done on knees)
10 burpees (step instead of jump)
15 sit-ups (crunches)
20 air squats (not as far down)
Rounds for Time means doing each of the exercises listed below it all at once, and then completing that 'circuit' 4 times through. To make it easier, do less rounds or decrease the amount of repetitions. You could also go through each exercise slower. To make it harder, increase the amount of rounds or amount of repetitions. Weight can also be added to the air squats, or you could try and do everything faster.