We've all probably seen similar graphs and I have for a long time attributed most cases of obesity to prolonged high fructose intakes. What I never stumbled across until now was a proposed mechanism:
Heavy fructose intake leads to elevated triglycerides.
Elevated triglycerides lead to reduced transport of leptin across the blood-brain barrier. Without proper leptin signalling, appetite isn't effectively managed, leading to an overall increase in food intake. If fructose constitutes X% of an individual's diet, and fructose increases the volume of food ingested, then it also increases the fructose intake, ensuring that an individual is locked into lipogenesis until fructose is removed.
RJ Johnson et al have put forth a theory that we have evolved toward an amplification of the effects of fructose by 1) losing the ability to endogenously create ascorbate, which increases the excretion of urate (a by-product of fructose metabolism) and 2) losing the enzyme uricase, which oxidizes uric acid. There was likely a time in our evolutionary history where this fructose-induced increase in adiposity was welcome and probably ensured our survival. Clearly, this is no longer the case.
Interestingly, the consumption of yeast also spikes uric acid due to the large amount of RNA that is being consumed (the breakdown of nucleotides leads to uric acid production). Perhaps a diet consisting of heavy bread/beer/fructose intake is even worse than fructose alone. Theobromine, present in chocolate and a byproduct of caffeine metabolism has the highest concentration of purines that I've seen. All of these things seem to factor heavily into the diets of the people residing in countries with the highest obesity rates.
This study showed that insulin resistance, hypertension, high triglycerides and weight gain were prevented by giving fructose-fed rats a uric-acid reducing agent as well. It seems to me that uric acid management is the key to all of this and that a simple approach to reverse/prevent obesity would simply be:
Avoid: fructose, bread and beer
Increase: vitamin c from low fructose sources (red bell peppers, strawberries etc.)
Edit: It occurs to me that the actual number of grams of theobromine ingested would probably be insignificant and that theobromine toxicity would likely be encountered before you ever got enough purines from it.