I just read the Eades link and it makes a lot of sense. And I do include cheese and nuts in my food protocol and have had the feeling I should be eating less as I mentioned before (although one is always struggling to wonder if that's just the CW whispering in my ear). However, having followed Art De Vany's site for a number of months now, read his book The New Evolution Diet and exchanged some comments with him through his forum I would add a few more points to consider ... and this is not intended to confuse further, merely to indicate this is a very complicated subject and there are no easy quick fixes for many people and no one solution.
Firstly, the body is a complex, chaotic energy system which cannot be accurately measured in terms of energy consumed (food in) over energy conserved (fat stored) over energy burned (used in living including exercise). It has evolved to be dynamic and works best out of equilibrium for the vast majority of the time. The body is rarely, if ever, in energy balance. So attempts at 'fine-tuning' are often futile and just generate frustration (cortisol) which just adds to the hormone pot that control EVERYTHING!
Secondly, hormones - we are our hormones, literally. Each one of us has a unique blueprint the hormones are working to, and each one of us arrives here a different level of damage to our hormonal systems. So each of our experiences of the PB are unique at a biochemical/endocrine level.
Obviously broad brush statements like more carbs = more insulin requirement are true, but at an individual level it's far more complex. For example you may be able to clear the small amount of glucose you consume with adequate insulin to have good fasted results. However, that doesn't necessarily mean that you have insulin-sensitive fat cells that will release their stores for you to burn! And there a lots of reasons for this, one will be gender, age of PBer, another medical history, another simply that you are eating enough fat to satisfy your body's needs and a big one (and still not well understood) will be medication.
So, thirdly, medication. My area of interest and further reading is bipolarity and I know that some of the drugs used in this disorder create insulin resistance. I also know that some of the same drugs are used in different dosages for other psychiatric issues including epilepsy and one assumes their insulin resistance effect is similar. Drugs used particularly post breast cancer are designed to inhibit the action of oestrogen (and this is highly associated with fat storage) - see Taubes' recounting of the rats with ovaries removed ... they became massively fat, when the oestrogen was restored they became lean.
Fourthly, the use of IFing. Art De Vany talks quite a bit about IFing as a way to trigger autophagy (ie cell clean up) and as a way of replicating to some extent the idea of intermittent food supply that we evolved with. However, he doesn't use it as a way of reducing food intake over the longer period and he notes that the body naturally wants to eat more following an IF in order to 'catch up' - and incidentally that is thought to be why all calorie-restricted dieters end up gaining back the weight lost over time, they just catch up the eating. He also uses it ad hoc, ie not to a schedule allowing it to occur naturally through the course of the week.
Fifthly (can you say that!), he would argue for a lower fat level. We are not talking low fat, or even moderate fat, but not excessive fat because he believes herein lies the path to overeating in terms of the energy we require in a world where we are not moving about as much as our ancestors did. This is very much what Eades is saying, you can keep your carbs very low but still consume a large amount of energy through high fat foods like cheese and nuts and adding lots of butter. He postulates that humans are by necessity lazy overeaters predisposed to take on board energy when it's available and to be lazy not to burn it excessively ready for times of scarcity. What we have to balance in modern life is the fact that real scarcity doesn't occur - we have to 'create' it to keep the body on its toes so to speak.
Sixthly (ditto!), insulin spiking. I think this may be relevant in the context of eating one large meal at the end of a fast. I suspect from all I've studied and n=1 that it makes more sense to spread your food over a window of time rather than load it at one meal, more a feeling about how I feel if I eat a big meal compared with two smaller ones - I'm more likely to be hungry after the big one than after two smaller ones.
Seventhly (I'm sure you can't say that but I'm on a roll!) you can quite easily under-eat, over-burn and still not lose weight - your body is just using your protein to fuel itself so your muscle mass is decreasing (which is heavier) whilst you get fatter, it isn't being created from thin air, it's being created from your muscle mass and bone density loss.
Eigthly, working with the system and tricking it! It seems that fasted training particularly for heavy lifting and sprinting triggers all kinds of good things in terms of insulin sensitivity, human growth hormone etc which will affect the way the body utilises the fuel you feed it and the fuel you already have stored. It also directly alters the hormone levels and metabolic rates.
So, summarizing in the light of Paleobird's case - a potential to have under-eaten through the IF regime combined with a possibility of overloading at one breaking fast meal (insulin spike?) if that is occurring with a good high fat meal that is going to be a fat storage issue. Combine that with too few calories when looked at over the longer term - ie week on week the body is perhaps assessing a scarcity scenario so less likely to burn fat supplies. On top of that you have the potential for medications playing a role in insulin resistance.
Like I said it's a totally complicated and complex situation and only trial and error is likely to find the 'key'. However, the more focus you apply, the more navel-gazing the higher the stress factors involved and that's just adding another layer to the mix.
All I do know is what you have been doing isn't giving you the result you desire so you do need to change something but deciding what isn't easy you have to make a call and run with it for a while and then review and try not to over-analyse in the interim.
Seeking the natural way in a modern world ...