Fascinating article which posits an argument that turns dietary theory on its head:
Inflammation might not be a symptom [of metabolic syndrome and obesity], it could be a cause. According to this theory, it is the immune activation caused by lousy food that prompts insulin and leptin resistance. Sugar builds up in your blood. Insulin increases. Your liver and pancreas strain to keep up. All because the loudly blaring danger signal — the inflammation — hampers your cells' ability to respond to hormonal signals...
Where does the perceived threat come from — all that inflammation? Some ingested fats are directly inflammatory. And dumping a huge amount of calories into the bloodstream from any source, be it fat or sugar, may overwhelm and inflame cells. But another source of inflammation is hidden in plain sight, the 100 trillion microbes inhabiting your gut.
Eating 'junk' food, it argues, promotes an unhealthy bacterial monoculture in our gut and this leads to the leakage of endotoxin from the gut into the body where it causes inflammation.
The advice at the end is relatively conventional: eat a wide variety of vegetables (including however high-carbohydrate wonders such as potatoes and fruit), along with perhaps some food that combine probiotic bacteria with prebiotic fibres such as kimchi, kefir and sauerkraut (unpasteurized and fermented for best results, presumably because this gives the highest bacterial load).
Food for thought!