I've heard that as well. But not 6 hours. That's a looong time.
I actually held to this rule when I first started on my journey. I set a time limit of about 7:00 or so to stop my eating. I needed to gain control of night time snacking and this was one of the ways that I did it.
I no longer hold to this anymore. I DID get my snacking under control so I no longer needed the rule. I tend to tweak things as I go along. Anyway, I started working out in the evenings and I look forward to a very
light snack in the evenings after I exercise. No more then 60 calories. My weightloss has not been affected.
I think it's more important the
amount of calories that you consume over the course of a day, then the time of day when you actually eat it. Like I said earlier though, I think it's okay to eat something light. If I were eating something heavy and caloric in the evenings that would leave me less food to eat during the day. Also going to bed shortly after eating a large meal could lead to indigestion.
If it's torture for you to not eat in the evenings, why not save up a few calories for an evening snack? You must set yourself up for success and find what works for you - and what doesn't. The easier it is on yourself and the more enjoyable the more likely it is you will stick to it.
