Do you really need to eat an hour after you take synthroid (thyroxine)?

30 min may suffice. If there is conflict in am, you can take at bedtime as shown in a recent study in a thyroid journal.
No. Most endocrinologists feel that it does not matter if you take your thyroid hormone on an empty stomach or with a meal or morning vs evening since even if you absorb a bit less taking it with food, the dosage can be adjusted based on your thyroid tests. You should however try to be consistent about whether you take well before eating or with food. lf you forget to take it one day take 2 next day.