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The Connection Between Food Allergy and Weight Gain

By Lucy Rose Clinic

July 21, 2022

Are you mystified by unexplained weight gain, even though you’ve bee counting yyour calories meticulously? If you’ve been diagnosed with food allergies or intolerances, an unexpected link may be at play. There is a perplexing connecction between food allergies and weight gain that is often overlooked and not fully understood. So welcome aboard! In this blog post, we’ll delve deep into the conundrum of food allergy-induced weight gain, offering insightful tips to take control of your weight and level-up your overall health. Let’s get started!

Could any of these foods be driving weight gain?

Food Allergy vs. Food Sensitivity

Many people use these two terms interchangeably, but in reality, they are two totally different immune system reactions. Think of it like a motorbike and a car. They are both vehicles of transport, but they are very different things!

What is a Food Allergy?

Food allergy is an immune system reaction that occurs soon after eating a certain food.  Food allergy occurs in around 5-10% of children and 2-4% of adults in Australia and New Zealand. Doctors usually perform skin testing or order blood tests for allergen specific Immunoglobulin E (antibodies) that help to identify or exclude potential food allergy triggers. Sometimes a medically supervised food allergen challenge is required to confirm or exclude food allergy.

The most common triggers of food allergy are;

  • Egg – particularly the whites
  • Cow’s milk (dairy)
  • Peanut
  • Tree nuts
  • Sesame
  • Soy
  • Wheat products
  • Fish and other seafood.

However, almost any food can cause an allergic reaction, including fruits!

Allergic reactions to foods range from mild to severe.

Mild to moderate symptoms of food allergy include swelling of the face, lips, and/or eyes, hives or welts on the skin, stomach (abdominal) pain, and vomiting. Severe reactions – called anaphylaxis – affect breathing and the heart, and can therefore be life-threatening.

Given the severity of food allergy, there’s a good chance that if you have one, you know about it and avoid those foods at all costs!

When it comes to stubborn weight issues, it could be a food intolerance that could be the cause.

The different immunoglobulin food reactions:

Immediate reactions (IGE) to food intolerances are fairly obvious as they occur soon after eating the problematic food.

Delayed reactions (IGG) are much harder to pinpoint as reactions can occur up to three days after consumption.

What is a food intolerance?

A food intolerance can present in a wide array of symptoms that are different for all people. The onset of these symptoms is also variable – from immediately, to 3 days later, and this varying time frame can constantly shift depending on multiple dietary and lifestyle factors.

Reactions to food intolerances can appear in many different forms, some not even related to the digestive system! Some examples of different reaction types are:

Weight Gain: Food can impact your body’s ability to lose weight if you have an intolerance to it – even if it is a “healthy” food choice.

Gastrointestinal: distension, bloating, gas, cramping, colic, IBS, diarrhea

Respiratory allergic reactions: rhinitis, nasal congestion, sinusitis

Dermal: Skin rashes, eczema, angioedema

Central Nervous System: mood swings, behavioural changes, learning difficulties

Neurovascular: migraines, Meniere’s disease (vertigo)

Musculoskeletal: weakness, feeling “below par”, arthralgia, myalgia

Could my food intolerance cause weight gain?

The short answer is yes, in a very indirect way.

Most commonly it is the inflammation which is a side effect of the food reaction in the gut that is the culprit of weight gain.

Chronic inflammation is the root cause of all disease, and it can be driven by other diseases lifestyle, diet, stress, and exercise levels. For thyroid patients, food intolerances cause a large contributing portion to their overall inflammation burden – which I’ll discuss next.

Chronic inflammation affects all the hormones, and is associated with increased weight gain, especially around the abdomen.

Left untreated, food sensitivities and allergies may also lead to weight gain because your level of fatigue affects how active you are.

This can lead to eating energy pick-me-ups loaded in sugar, for that bolt of energy, but the payoff a few hours later is a disrupted blood sugar balance. Imbalances in your blood sugars over a long period of time can lead to pre-diabetes and metabolic syndrome – 2 conditions that people find very hard to lose weight with.

The thyroid and food intolerance connection

If you have a thyroid imbalance, then you are likely to have developed several food intolerances.

Even if your TSH tests have come back as “normal” but you still have symptoms of fatigue and weight gain, it pays to have a more accurate and specific thyroid test done to truly assess your thyroid.

Listen to our podcast which explains why you shouldn’t rely on standard TSH;

Even a sub-optimal thyroid affects your entire body!

Many studies show that the thyroid has a direct impact on your gut.

Studies have shown that there is a reduction in esophageal and gastric motility in hypothyroidism. Reduced motility and low stomach acid also cause increased bacterial growth in the small intestine; a condition known as Small Intestinal Bacterial Overgrowth (SIBO).

Hashimoto’s disease is associated with reduced esophageal motility which presents as nausea, vomiting, bloating, dysphagia (difficulty swallowing), and heartburn.

Common synthetic thyroid medications may contain excipients such as lactose that cause bloating and discomfort, and these excipients are cumulative.

Check Your Thyroid At Home Test

Check your waking temperature. A reading below the normal 36.6°C (add 1 degree to under the arm temperature) strongly suggests hypothyroid. A reading above 36.7°C may indicate hyperthyroidism (overactive thyroid).

How to discover your individual food intolerances

Thanks to science, you can discover your food intolerances with a simple blood test.

This simple blood test is able to measure your delayed reactions to 59 different food types. Using immunoglobulins, this test is able to see if you have a particular intolerance to certain food types by their reactions in your blood sample.

No strict diet restrictions and food diary keeping, a simple blood sample is sent to the lab where they put your blood against 59 different food proteins, then analyse the results. The more IgG antibodies your blood makes, the stronger the food reaction in your body.

Client Case Review

The test result further down is from a lovely lady who struggled with weight, but her thyroid was considered ‘normal’.

We ran testing on all her hormones and nutrients, and what we discovered were elevated inflammatory markers, LOW cortisol, LOW fT3 (the active thyroid hormone), HIGH blood glucose, and HIGH LEPTIN.

From a diet perspective, she thought she was eating really healthy! This was her diet BEFORE seeing her food intolerance report:

↓ ↓ ↓

Breakfast: Uncle Tobys Cereal Shredded Wheat with low fat milk (cow) topped with nuts and berries. (Cashew, hazelnut, walnut, blueberries)

Mid-morning snack: cup of tea (cow milk) rice cake with peanut butter. Maybe a sweet biscuit (Arnott’s brand) if they are around.

Lunch: Wrap (wheat) with salad and egg, or salad and tuna. Sometimes something from a bakery (pie or toastie)

Afternoon snack: sometimes a boiled egg, or some nuts and fruit

Dinner: Chicken/beef/lamb or occasional fish with vege. Pasta dish 3-4 times a week. Use of flour for thickening casseroles.

What do YOU think of her diet?

Have a look at her food intolerance report below and then think again!

Red indicates that a strong positive reaction has occurred

Orange indicates a medium reaction

Yellow indicates a weaker positive reaction.

If the reaction is normal, the colour will remain Blue


Once you find out her actual food intolerances, you can see that the MAJORITY of her diet is inflammatory to her system!

She immediately stopped eating all the foods coloured Red, Orange, and Yellow, and felt immediate relief from postnasal drip and phlegmy cough.

Day 2 she had the best bowel movement of her life (Her words!)

Day 3 she lost 3 kilos.

Her body was so inflamed from her diet that it was holding a lot of fluid weight, and once she stopped eating those trigger foods, the weight literally dropped away. She felt amazing too!

If you feel that you have hidden food intolerances affecting your weight and health, book a free introductory phone call – click here to book.

Or you can call us too – 1300 THYROID (1300 849 764)

Inflammation is the biggest factor we need to address when dealing with any hormone imbalance, but especially LEPTIN excess, and finding the cause of the chronic inflammation is a vital key to unlocking the door to weight loss.

This is where we excel!

To access this test and discover what else you need to solve the metabolism puzzle, please contact us! Book in a free 15-Minute Appointment we’d love to connect and discuss how we can help you feel great!

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