Could It Be Something You Ate?

Find out if overlooked food allergies or intolerances might be interfering with your weight-loss and fitness goals.

Are you working out and watching what you eat but still struggling to lose weight? Do you sometimes feel suddenly tired and bloated for no apparent reason – and then break your gym date as a result? If so, it’s possible that a food allergy or intolerance is the culprit. Often overlooked by medical professionals, food intolerances can cause or exacerbate “UFOs” (Unidentified Fitness Obstacles) by sapping your energy and interfering with weight-loss efforts. Fortunately, identifying (and correcting) them can be relatively easy.

Allergy or Intolerance?

While food allergies and intolerances often have symptoms that overlap, the difference between the two problems is distinct. A food allergy is when your body wrongly perceives that a food is hazardous to your health and triggers an immune response. You develop antibodies to fight the allergy-causing food, much as you would if you were allergic to penicillin or some other drug.

Each time you consume an allergy-causing food, your body releases chemicals – in particular, histamines – to combat the problem food. This could trigger a whole cascade of symptoms, ranging from mild congestion to profound fatigue. But food allergies don’t necessarily strike right away, nor are they always severe. In some cases, symptoms – such as diarrhea, abdominal cramps, an “itchy” mouth, hives, eczema and fatigue – develop gradually and become more pronounced over time. People often don’t realize that they’re allergic to a food, either because their reaction is delayed and mild or because they attribute their allergy symptoms to something else. Common allergy-causing foods include legumes, fish, shellfish, eggs, peanuts and most tree nuts.

Food intolerances, on the other hand, occur when your body lacks or does not produce enough of an enzyme required to break down a certain type of food. For example, the enzyme lactase is required to digest the sugar in milk. If you don’t have the proper enzymes to digest a food, it will linger in the stomach, resulting in fermentation, which produces excess gas and intestinal irritation.

Another cause of food-intolerance symptoms is weak-walled intestines – sometimes called “leaky gut” syndrome. When food “leaks” through the intestinal walls, it enters the bloodstream as a toxin. This can result in anemia and nutrient malabsorption, which can cause a variety of additional problems, ranging from weight gain to constant fatigue and lowered immunity. Other food-intolerance symptoms include stomach cramps and a rapid pulse, perspiration and diarrhea, as well as sinusitis, problems with sleep, anxiety, constipation, fluid retention and brittle nails.

When it comes to intolerance-causing foods, wheat, gluten and yeast head the list, closely followed by dairy foods such as milk, ice cream, cheese and yogurt. Mushrooms, coffee, corn, peppers and fruit also can be problematic, as can preservatives (sulfates) and flavor enhancers such as MSG. (See “Excitotoxins” in the March/April 2003 Experience Life, available in the archives at

Food-intolerance symptoms can take days to manifest, making it hard to identify the cause. And quite often, the foods we crave are the very ones we tolerate least. (For more on this phenomenon, see “False Fat” by Elson Haas, MD, in the March/April 2003 Experience Life.) Some experts believe that this is because key nutrients aren’t absorbed, which signals the body to crave more of the same food in order to fill the void.

Clearing Out

Once you identify food allergies and intolerances, and alter your diet accordingly, you may be amazed at how quickly and dramatically the change improves your physical well-being.

My client Mandy tried many different weight-loss plans, but no matter how well she followed them, her weight remained the same. At first, she tried low-carb plans and began to consume more dairy foods like cottage cheese, yogurt and milk. But although her friends were losing weight while following the same plan, Mandy had no such luck. Plus she always felt bloated and had little energy to work out.

When Mandy revealed her symptoms – bloating, gas, stomach cramps and fatigue – I surmised that lactose intolerance might be to blame. Sure enough, after her doctor confirmed that dairy foods were likely to be a problem for Mandy, she removed them from her diet and quickly felt her energy soar. Soon, her excess weight began dropping away.

Another client, Susan, was also struggling with unexplained weight gain and bouts of fatigue that forced her to skip workouts. I asked her to keep a food log for a couple of weeks, noting what she ate throughout the day and how she felt afterward. By doing this, she was able to see that she felt bad whenever she consumed any type of nut. She said that she often ate nuts because they were such a “healthy snack,” but she never noticed that eating them had any connection to the brain fog, indigestion and fatigue she experienced throughout a typical day. “By addressing my food allergy, I soon lost 10 pounds,” Susan said. “It helped me get my energy back so I wouldn’t keep skipping my run.”

If you suspect you have a food allergy or intolerance, write down all the foods you consume for one to two weeks. Record any symptoms you have, when they occurred and to what extent. Then see a doctor or naturopath to talk about your results. It may be your key to regaining your energy, losing your excess weight and keeping it off for good.

Michael Gerrish, MS, is the author of The Mind-Body Makeover Project: A 12-Week Plan for Transforming Your Body and Your Life (McGraw-Hill, 2003) and When Working Out Isn't Working Out: A Mind-Body Guide to Conquering Unidentified Fitness Obstacles (St. Martin's Press, 1999). Formerly a conditioning consultant for the Boston Red Sox and Boston Bruins, he is an exercise physiologist, psychotherapist and certified thought-field therapist. He lives in Massachusetts. Visit his Web site at

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