The fastest way to increase your metabolism while maintaining excellent function is to change the thermal coefficient of the environment you live and work out in. It has the greatest effect on REE. Sadly most people who calculate REE do not even know it. I use REE and this in my own regime and it is unbelievably effective for diabetes reversals.

IF once a month for 23 hours is a good idea. This is two meals. Maybe on a weekend or sometime where perfromance is not as critical.

The current research/understanding is that eating more only speeds up the metabolism to the extent necessary to handle the extra food - there's no 'additional burn'. However you may find it an easier model to work with which may bring benefits. I would view it as treating the symptoms rather than the problem itself, and that it may not be the absolute best thing to do, but eating frequently may be better than what you're currently doing. The risk is that it allows you to ignore some other more fundamental problem with your lifestyle.

I don't see why it would cause problems. IMO it's important to do what's most natural for you.

I always preferred large meals and was frustrated and dysfunctional on frequent meals. Okay, that means IF is a great choice for me. It doesn't mean IF has to be the best option for you.

Let's face it, there's a wide range of "normal" on everything related to humans. You need to feel free to discover where you best fit into that range and act accordingly.

P.S. In fact, as I think about it if IF is a great weight-loss solution for me who says eating frequently can't be an enhanced-nutrition mechanism for you? Just make sure you always emphasize denser foods rather than volume (again, the opposite of what I do to lose.)

When you say you cannot eat enough, is it mostly related to the colon issue you mentioned? I suppose you may have to look at higher calorie choices. Or is it just that you a 'full' and so cannot eat more?

I only eat two meals a day, lunch and dinner (post work-out) and I generally hit my calorie target.

Another Leangains FAQ which may provide some further ideas and links: http://examine.com/leangains-faq/

"Can I Bulk with the LG Approach or is Strictly to Lose Fat?
LG is not about just losing fat. It is about recomposition. So yes you can bulk - just eat above your maintenance. LG will help you lose BF, and it will let you get to low BF% levels, but the overall focus is on recomposition. Martin has said that LG is essentially a self-contained cut/bulk - 16 hours of cut, 8 hours of bulk."

Meal frequency is irrelevant to body metabolism: http://examine.com/faq/do-i-need-to-eat-six-times-a-day-to-keep-my-metabolism-high.html

I wonder if your inability to eat massive amounts of food has something to do with gut flora and/or stomach acid levels.

Perhaps you might try supplementing with a bunch of either digestive enzymes (i.e. Now Super Enzymes) or betaine HCL before meals and seeing if your digestion speeds up.

For these you'd want to first figure out how many you need by taking them before you eat, say one pill at a time, spaced out by a minute or two until you feel heat with your hand above your stomach (or feel heartburn), upto a total of 5 pills.

Failing that, if the issue isn't in the stomach, the usual gut flora improvements via sour kraut, kefir and other probiotics as well as bone broths, etc.

I IF and I find I'm naturally hungrier 2 or 3 days out of the week. I listen to my body and eat a lot more during those days. It doesn't seem to affect my weight loss faster or slower but I do take coconut oil before meals to keep my cravings at bay on re-feeding days.