No, because “brain” and “muscles” are different things. In fact, it's the opposite, it's a way to satisfy a desire which would reinforce health and weight loss, without actually reaping any of the benefits.

Didn't some recent research show that merely visualising exercise had measurable physical benefits?

If I recall it was about weight lifting and mentally visualizing the lifts in tandem with actual exercise. Pretty sure just thinking by itself did nothing. So, it was three way comparison (lifting alone, visualizing plus lifting, and just visualizing).

Edit: this is not that study but, along the same lines .. https://www.ncbi.nlm.nih.gov/pubmed/14998709/ pretty tiny sample though

In general, visualization improves performance of ant activity.

The benefit is supposed to be that your technique will be better. Your muscles won't become stronger unless you exercise them.

There is actually some reason to believe that imagining can increase the strength, for example this study: https://web.archive.org/web/20170814100324/http://jn.physiol...

Probably the opposite, because your brain thinks it did exercise, so: hungry!

Except you didn't actually burn the calories...

I watch fotball while exercising on my spinning bike. Highly recommend!