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6 Ways Food Sensitivities Influence Weight Loss

By Samantha Bielawski, RD

Fifty years ago, food allergies seemed almost non-existent.

In the last few years, however, gluten-free, dairy-free, yeast-free, or nut-free have become commonplace dietary approaches. There are allergen-free cookbooks, peanut-free schools, egg-free cupcakes and so on.

Unfortunately, it’s not just a fad. By the time you’re done reading this article, someone will have been rushed to the emergency room for an allergic reaction to food. Since the mid-1990s, food allergies have increased by 50%, and the numbers are growing. The fair and necessary question arises: what’s going on here?

While experts are still exploring the potential causes behind the dramatic rise in food reactions, it’s widely recognized that they’re multi-factorial. When the causes are many, so are the impacts.

There are several types of reactions to food. For example, an enzymatic deficiency can result in gas, bloating and pain. An IgE immune-mediated reaction can trigger anaphylaxis. Even a seemingly subtle sensitivity can have far-reaching and highly varied delayed impacts – everything from eczema to excess phlegm production to trouble losing weight.

In my practice as a dietitian, I see more and more clients achieve weight loss success with the results of a food sensitivity profile. One client lost four pounds over one weekend simply by eliminating the foods to which she was most severely sensitive.

What makes their stories even more rewarding are the reports of increased energy, better glucose control, improved mental clarity, better appetite regulation, and clearing eczema.

Could food sensitivities be the culprit for you? Check out the following six ways that undetected food sensitivities may be impacting your weight loss endeavor!

Blood Glucose Control

Many of us know to manage stress, focus on protein and fiber, and moderate carbohydrate intake for optimal blood sugar control.

If you’ve mastered those habits and continue to struggle to gain control of your blood sugar, food sensitivities may be to blame.

With chronic exposure to a food that triggers an exaggerated immune response, excess cortisol production can cause your blood sugar to rise. Insulin receptors may even become damaged, thereby increasing levels of the primary fat-storage hormone in your blood.

Thyroid Issues

Did you know that sub-optimal thyroid functioning can decrease metabolism by up to 40%? That’s a big problem for many reasons but even more so if your goal is weight loss.

Hashimoto’s thyroiditis, an autoimmune condition, is one of the most common causes of thyroid disruption. Much of our immune functioning is seated in the health of our gastrointestinal tract. (In fact, much of our overall health lies in the functioning of our GI tract, which is no surprise given the surface area of our small intestine could cover a tennis court!)

Even if your thyroid condition is not autoimmune in nature, you might not be out of the woods. A good portion of our active thyroid hormone, T3, is formed from conversion processes in our intestines.

Undiagnosed food sensitivities can wreak havoc on our intestinal health and functioning.

Belly Fat

Abdominal fat seems to be enemy number one for those trying to lose weight, and it’s closely related to your body’s production of cortisol, one of our many stress hormones.

When you have an immune response to food, your body is flooded with a host of inflammatory compounds – cortisol included. If you carry most of your weight in your midsection, consider food sensitivities as a possible contributor to your growing waistline.

Food Addiction

One thing that triggers immense frustration in an educated nutrition professional is the unfair societal judgment cast on those who struggle with food addiction. Yes, it is very real. Food addiction is psychologically complex, and it is physiologically real.

Within the complicated picture and progression of food addiction, food sensitivities and allergies can contribute to or worsen a person’s spiral in unrecognized ways.

Food that causes a delayed immune reaction, which can go on for years and be almost impossible to detect without a blood test, for example, can create a physiologically “addictive” response cycle.

Cravings and Mood

Serotonin is an important neurotransmitter involved in GI function, mood, appetite and sleep. Serotonin levels can dip from the impact of chronic exposure to foods that induce an immune-based reaction.

In turn, our satiety signals may be disrupted, and we may have trouble feeling satisfied after meals. Dips in serotonin are also a common cause for sugar and carbohydrate cravings as well as mood swings.

The fact is, we all know we should limit carbohydrates, eat only until we’re satisfied and get plenty of exercise. The problem is, however, these are harder choices to make if we’re dealing with physiological cravings, skewed satiety signals or mood swings.

If a food sensitivity leaves us continually reeling in all three of these ways, we’re more likely to significantly struggle with maintaining a healthy diet of vegetables and proteins or a consistent exercise regimen. Probing the possibility – and impact – of food sensitivities allows us to get to a primary root cause of our difficulties and helps us achieve real, long-term results.


The importance of seven to eight hours of quality sleep is critical in any health journey.

But did you know that the gut actually contains 400 times the melatonin of our pineal gland?[i] Melatonin is crucial to our sleep/wake cycles.

In keeping with that fact, the overall health and vitality of the gastrointestinal tract must be considered to improve sleep quality. Given that one in three of us[ii] struggles with insomnia, exploring the possible role of food sensitivities might prove a productive inquiry – for better sleep and weight loss.

Discovering and addressing food sensitivity is critical, given the far-reaching impacts of the resulting exaggerated immune response. Have you been tested or tried an elimination diet?

Consult a registered dietitian about whether food sensitivities could be holding back your weight loss progress! Thanks for reading.

[i] Chen, C.-Q., Fichna, J., Bashashati, M., Li, Y.-Y., & Storr, M. (2011). Distribution, function and physiological role of melatonin in the lower gut. World Journal of Gastroenterolgy: WJG, 17(34), 3888-3898.

[ii] Roth, T. (2007). Insomnia: Definition, Prevalence, Etiology, and Consequences. Journal of Clinical Sleep Medicine: JCSM: Official Publication of the American Academy of Sleep Medicine, 3(5 Suppl), S7-S10.

The posts on this blog are not intended to suggest or recommend the diagnosis, treatment, cure, or prevention of any disease, nor to substitute for medical treatment, nor to be an alternative to medical advice. The use of the suggestions and recommendations on this blog post is at the choice and risk of the reader.
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