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Digestive problems, allergies and obesity are among the list of ailments that sufferers said improved after switching to a non-GMO diet

Switching to a non-GMO diet can transform health for the better, according to survey results reported in a new peer-reviewed article by Jeffrey M. Smith, published in the International Journal of Human Nutrition and Functional Medicine.

Out of 3,256 people who responded to a survey emailed to members of the database of Smith’s organisation, the Institute for Responsible Technology (IRT), a remarkable 85.2% said their digestive health improved – by far the number one self-reported benefit – on changing to a diet without GMOs.

Moreover, the changes were significant. When the 85% was broken down, only 5.9% reported “some mild improvement” and 11.3% “moderate improvement”. A full 29.1% reported “significant improvement,” 22.2% said their condition had “nearly gone,” and 16.6% had a “complete recovery.”

That means that more than two-thirds of everyone who answered the survey reported at least a significant improvement — up to complete recovery — from digestive problems after adopting a non-GMO diet.

Fatigue was next on the list of the most frequently improved conditions, with 60.4% of respondents reporting an improvement. For overweight and obesity, the proportion of respondents reporting improvement was 54.6%; for “brain fog”, it was 51.7%; while for food allergies or sensitivities, it was 50.2%. Insomnia, skin problems, seasonal allergies, gluten sensitivity, musculoskeletal pain, and diabetes were also reported as decreasing.

Confounding factors

There are a number of confounding factors that influence how the results can be interpreted.

First, GM foods don’t have to be labelled in the US. So people who wish to avoid eating them often choose to eat organic, since organic foods are not allowed to intentionally contain GMOs. However, organic production also bans many toxic pesticides that are routinely sprayed on GM and non-organic non-GM foods. So improvements in health seen on adopting a non-GMO diet may be due in part or in full to reducing or eliminating exposure to these pesticides, as Smith explains in his paper.

In addition, most GMOs are found in processed foods, in the form of derivatives of soy, corn, cottonseed, canola and sugar beets. Smith notes: “Many people choose to avoid GMOs by reducing consumption of processed foods. Therefore, health improvements may be related to the benefits of unprocessed foods.”

Another factor, as Smith writes, is that some healthcare practitioners who prescribe a non-GMO diet to patients also recommend eliminating gluten and/or dairy, which may contribute to the health improvements.

Smith acknowledges that without carefully controlled human clinical trials, it is not possible to assess to what extent the GMO component of the diet is causing health problems. However, he points out that results from some controlled animal feeding studies show health impacts of GM foods, many of them related to digestive function. These studies are summarised and referenced in his new paper.

As well, Smith writes, “Based on informal surveys and conversations… farmers and veterinarians describe improvements in livestock that are switched to non-GMO soy, corn, or both. In livestock, there are generally no other dietary changes and the reported improvements, e.g. gastrointestinal, immune, irritable or aggressive behaviour, fatigue level, skin health, etc. are similar or identical to those reported by individuals and their practitioners.”


Smith admits in his paper that this was a “self-selecting survey of a non-representative sample of the population”. He explains, “IRT is a leading advocacy group that educates people on the health dangers of GMOs. The results of this survey are therefore limited to a population that is already aware of GM crops and has been exposed to information about the negative health impacts. Some percentage of the respondents may be biased towards attributing health improvements to the elimination of GMOs based on expectations.”

However, he adds that this database also gave him rare access to a group of people who were ripe for a study of this type, since they “have become educated about GM food risks, eliminated them, and may have noticed a change as a result”.


Cynics might ascribe the positive changes reported to the placebo effect: People who are already suspicious of GMOs will naturally feel better if they eliminate them from their dinner plates.

But in view of the scientifically proven power of the placebo effect, what’s not to like about the non-GMO diet? After all, it appears to be remarkably efficient at harnessing this phenomenon, with the end result that people feel better.

So whichever way you look at it, switching to a non-GMO diet seems to be good for people.