Without getting too scientific, I've found it's very difficult to gain weight no matter what I eat if I walk or run 6 miles a day. For bicycling, it's about 18 miles a day.

My diet has varied a lot over the years, so I'm not sure it makes a lot of difference as long as it's reasonable.

My interest in when I started this thread was simply to find a lighter weight way to avoid the food mood after the third day. I haven't found an answer yet.