Research by Wilders-Truschnig et al (2008) from the Clinical Institute of Medical and Chemical Laboratory Diagnostics in Austria have shown that obese children have significantly higher IgG antibodies against certain food antigens than normal weight children. These IgG antibodies are associated with low grade systemic inflammation (the silent inflammation that Barry Sears talks about) and with thickening of the common carotid arteries. The authors state that these findings raise the possibility that IgG mediated food antigens are pathogenetically involved in the development of obesity and atherosclerosis.
Food intolerances do not cause anaphylactic shock or hives that a food allergy would cause – they cause more of a low level / subclinical irritation of the gut and immune system. Conventional medicine and dieticians may tell you there is no such thing as food intolerances; however you can easily test yourself with a reliable test called York Test. You can also see that food manufacturers are now embracing this idea and providing foods that are gluten, wheat or dairy free. The most common food intolerances are indeed those foods plus yeast and eggs.
Wilders-Truschnig M, Mangge H, Lieners C, Gruber H, Mayer C, März W. (2008) IgG antibodies against food antigens are correlated with inflammation and intima media thickness in obese juveniles. Exp Clin Endocrinol Diabetes. 116(4): 241-5.