Don't undo a good session at the fridge. What to eat afterwards depends on what you just did.
After a hard workout the temptation is to eat everything — the trick is matching the fuel to the effort. A simple guide: a 30-minute jog just needs a glass of water; 45 minutes of cardio, a light snack under 100 kcal (a glass of low-fat yogurt); a 90-minute intense session, a ~150-kcal snack like a jam or cheese sandwich; and an hour of strength work, your normal meal for that time of day, eaten about 30 minutes after.
Want to get more out of every session? Three ways to raise your post-workout metabolism: train in the morning, use supersets with plenty of variations per muscle group, and every 2–3 weeks do one full-body workout.
And an easy everyday win: an apple. They help keep brain cells young and may even help protect the body against allergies.