There is a direct connection between allergy and weight gain. It is due to the interaction between fat cells and the cells that create allergic responses, the mast cells.

Mast cells store dozens of chemicals that create inflammation. Whenever there's an allergic reaction, mast cells dump these chemicals into your tissues, where they produce most of the common symptoms of allergy, like itching, swelling, redness, sneezing, and wheezing. A little-known fact is that some of these chemicals also promote the growth of fat cells.

Fat cells, for their part, also store many chemicals. As you gain weight, these chemicals are released by the fat cells and circulate in your blood. Most of them provoke more inflammation.

There’s something in your fat cells that does the opposite: a hormone that reduces inflammation. It is called adiponectin. Adiponectin has direct anti-allergic effects. It calms down eosinophils (Eos), cells that release enzymes that can damage tissues and harm your immune system.

Here’s the problem: the larger your fat cells, the less adiponectin they make. So as your fat cells get fatter, the Eos get restless and produce more allergic inflammation, which increases activation of mast cells, which promotes the growth of fat.

I believe that this vicious cycle explains the powerful link between having allergies and being overweight, a connection that has been documented in medical research. The science shows us:

• Increased body fat is associated with increased prevalence of asthma, allergic rhinitis, and eczema.
• People with chronic allergic sinusitis are two and a half times more likely to be overweight than a control population without allergies.
• Use of prescription antihistamines, a sign of clinical allergy, is associated with increased body weight, according to a study done at Yale University utilizing data from the U.S. government’s National Health and Nutrition Examination Survey.
• For children and adolescents, being overweight or obese increases blood levels of allergic IgE antibodies, especially to food.
• Even for women of normal weight, an increase in waist size increases the risk and severity of asthma. The implications of this are very serious, because the rate of abdominal obesity among women in the United States is almost twice the rate of general obesity and reflects a heightened state of inflammation in the body. The inflammatory effect of excess abdominal fat may explain why weight loss by itself improves asthma control in people who are overweight.
   

Below are 5 foods most likely to prevent weight loss because of allergy:
 

• Wheat and products made from wheat. Remember that white flour is just refined wheat flour. Wheat is the main ingredient in most breads, crackers, pastries, pasta, and noodles. It’s also used to thicken sauces, soups, jams, and jellies.
   
• Milk and milk products, which include cheese, yogurt, cream, ice cream, and butter. Milk solids or milk proteins like casein or whey are often added to prepared foods, so check ingredient lists to be sure you’re avoiding milk products in all forms.
   
• Yeast, which is added to bread and other baked goods as well as to beer and commercial soups and sauces. It also occurs naturally on the surfaces of many fruits and vegetables. Vinegar, wine, sauerkraut, and other fermented foods often contain yeast proteins. So do dried fruits and commercial fruit juices and ciders.
   
• Soy, which is often added to foods as soy protein or soybean oil or lecithin. Soy as an ingredient is often listed under an alias, such as textured or hydrolyzed vegetable protein, vegetable oil, or mono- and diglycerides. Soy may be a hidden ingredient in foods such as sausage, doughnuts, and bouillon cubes. It’s used in many canned foods, fast foods, baked goods, luncheon meats, ice creams, and chocolates.
   
• Corn, which is widely distributed in our food supply as corn syrup, cornstarch, corn sweetener, and corn oil or hidden under an alias as dextrose or maltodextrin. When xanthan gum, acetic acid, ethyl acetate, ascorbic acid (vitamin C), or vanilla extract appears on a food label, corn was probably the source from which it was made. Corn is the foundation of U.S. agribusiness.

In my book, The Allergy Solution, you will find my Immune Balance Diet to boost adiponectin, the anti-allergic hormone that increases when you lose weight. Scien­tific studies have shown that specific foods or food components can increase production of adiponectin by fat cells in a direct fashion, independent of body weight.