Have you eaten enough today to fuel your workout? The Back to Fit circuit workouts demand a lot of energy, so it's important to keep yourself properly fed throughout the day. If you find you run out of food throughout the day, use the next rest day to plan a full week of meals. Trust us, it'll help so much in the long run.
Bill Phillip's Back To Fit: Day 18
If your energy is flagging in the gym, check your nutrition!