I've been on this board daily for several months now and never heard that complaint before. I'm no expert but I would be inclined to say that it's associated with menopause or perimenopause (but you didn't state your age?). Your body should have made the metabolic switch to lipolysis by now, so I don't think it would be associated with your diet.... unless you ate something particulary spicy. For instance, red pepper (ceyenne) will definitely give you hot flashes if you eat enough of it.

As for your "stall".... you haven't stalled. A period of no weight loss is very common in week 2-3. Just stick with your plan and the scale will move again! 7 lbs is great!! During the first two weeks you can expect to lose about 10% of your desired weight loss. After that, a rate of about 5% per month is average. You're doing fine.