If you were eating very low carb and moderate/low fat before and have now added more fat and more carbs, then I think it's only to be expected that you might gain weight, whatever theory of fat accumulation you hold to.
Do calories actually matter?
Yes, absolutely. I've not read anything by Taubes that suggests otherwise. Also, from a paleo perspective, it would be incredibly awkward if you couldn't maintain or add to fat stores in the absence of carbohydrate. If, after felling some huge wild animal, everybody could only spill any calories consumed after ~2500 into the ether, it would be highly unfortunate. Let's assume that when eating no carbohydrates your body is a perfectly efficient fat-burning machine, so it happily burns through x calories of fat every day. It is not unreasonable to think that if you consume substantially more than x calories of fat, then the body can (and very possibly, will) accumulate more fat. Two of the prime reasons why people don't gain fat in such a state is because they spontaneously don't eat x+ calories and because if they do eat x+ calories one day, leptin ensures that they eat commensurately less calories the next day. Now there are assorted over-feeding studies that show that some people, when stuffing themselves with as many calories as they can still can't gain substantial amounts of weight and there are various ways that the body can respond to an excess of calories (in addition to reducing future calorie intake), but leaving aside these complexities, it's clearly not impossible to increase fat levels by consuming more fat than you'd usually burn.
Of course, if you also added extra carbs to your diet at the same time then, it's even more plausible that you might gain weight. I gained about a stone just from increasing my carbs up to around 40g a day, without any other conscious change in my diet. Also I would bear in mind that the effects of the holiday sugar binge could be impeding your progress even now, since no matter how low carb you're eating, a large amount of carbs will have restocked your supplies of glycogen (and added water and so on). I didn't know about Dr K's point that it would reduce leptin sensitivity, but it will certainly impact insulin sensitivity (because the muscles/liver are no longer empty to soak up glucose).
Your described daily meals above sound very low in calories, so I can't see any obvious changes to make. I don't see where you'd be getting up to 100g of carbs from since the spinach and avocado together equal about 8g/25g net/total carbs.
There doesn't seem to be anything particularly wrong with what you're eating, so you can only try reducing the fat and/or reducing the carbs. My own bias suggests cutting back on the 50/100g of carbs first and seeing whether this means you can effortlessly lose weight without conscious calorie restriction. If not, then try reducing the fat (i.e. eating as little as you need to feel satiated). Of course, you could also try eating more protein (which is uncontroversially satiating) and see whether this allows you to reduce carbs/fat.
