If it is ok to train two days in a row, ensuring that you don't work the same muscle group on each day, then why as templates suggest, do we not lift on the third,sixth and seventh day?wwxwwxx. If you ensure that you don't work the same muscle group two days in a row, then why not lift everyday. It would appear that the whole body needs a rest day, but why?
Because your body is a unit, not a collection of "muscle groups."
Muscles don't grow in the gym. They grow when they are rested and nourished outside
the gym, provided that they were properly challenged by your workout. If you perform low-intensity workouts, you could exercise every day. But if your aim is to build muscle, you have to train hard then take time off to recover. The further you progress in weight training, the more crucial rest becomes for you to continue to progress.
And while I'm here, has any one had adverse effects from eating a lot of tuna. I thought tuna (being high in protein) in Wholemeal bread would be a quick and easy small meal to eat throughout the day while at work. Perhaps not!
The adverse effect that I've had with tuna is bad breath. Eating tuna all day is not recommended if you have a hot date that night. ;-)
Seriously, there are some concerns with the level of mercury in tuna, so eating it indiscriminately might be problematic for some people. But most dieticians would recommend eating a varied diet so all your nutritional bases are covered. Tuna and whole grain bread have little vitamin A or C, for example. Maybe try topping your sandwich with romaine lettuce and tomato, or eat some fruit.