Diabetes is one of the biggest public health challenges of the 21st century because of the costs associated with its management, which are estimated at more than three billion dollars per year in Quebec. This cost has been growing steadily for 20 years now. A person with controlled diabetes mobilizes three times more medical resources than a person without diabetes (Diabetes Quebec, 2009). This amount increases rapidly with the associated complications. Therapeutic carbohydrate restriction (in an omnivorous context) used specifically to control glycemia is being studied more and more, but has never been verified in a vegan context. Some studies show that a vegan diet could be an effective way to help type 2 diabetics (T2DM) to better manage their blood sugar. Thus, it is necessary to question whether these effects can be accentuated in the context of a low or very low carbohydrate diet. Numerous publications have highlighted the role of the gut microbiota in metabolic diseases, including T2DM. Analysis of the microbiome before and after dietary change combined with daily breath testing will tell us more about possible intolerances and the role of the microbiome in T2DM management. Given the novelty of these hypotheses and its absence in the literature, it is relevant to undertake a first pilot project with a smaller number of participants in order to obtain preliminary data that will allow us to define more precisely the research avenues for a subsequent study.

In recent years, there has been an explosion in the prevalence of obesity and type 2 diabetes (T2DM) worldwide. Obesity, high blood pressure, excessive insulin secretion and other risk factors are precursors to serious or chronic health problems such as diabetes. Type 2 diabetes, which affects more than 8.1% of the Quebec population (2017-2018), has an average annual increase in prevalence of 3.3%, not to mention its devastating direct and indirect consequences on cardiometabolic health and its astronomical costs for the health system.This is now a global concern for which researchers, health experts, and physicians are working together to find practical solutions. In 2016, more than 3.8 million deaths were directly attributed to diabetes or high blood sugar. The number of indirect deaths related to diabetes, however, is difficult to estimate. Despite this, there are strong evidences that diabetes increases the risk of cardiovascular disease, stroke and kidney failure.

Many physicians around the world use low-carbohydrate or ketogenic diets to reverse T2DM. Dr. Evelyne Bourdua-Roy, of the Reversa Clinic, has been doing that since January 2017. Over 2000 patients have chosen the clinic to eat differently in order to learn to better manage their obesity, hypertension, type 2 diabetes and related comorbidities. As a result of the strategies proposed by the Reversa Clinic, many medications are regularly reduced or completely stopped as a result of the changes made in the patients' diet. This results in substantial savings for patients and the health care system. It also results in improved patient health (glycated hemoglobin [HbA1c], C-reactive protein [CRP], hypertension, etc.). New guidelines released by the American Diabetes Association, Diabetes Australia and Diabetes UK now recognize low and very low carbohydrate diets as secure and effective treatments to improve blood sugar levels and to help manage blood sugar variations and thus better manage this disease. With over 8% of the population affected by the disease, Diabetes Canada issued a statement to this effect in the spring of 2020.

The low-carbohydrate diet in an omnivorous context is being studied more and more, but has never been verified in a vegetarian context.

Several studies show that a vegan diet may be an effective way to help T2DM's better manage their blood glucose. Thus, one must question whether these effects can be accentuated in the context of a low or very low carbohydrate diet. Given the novelty of this hypothesis and its absence in the literature, it is relevant to undertake a first pilot project with a smaller number of participants in order to obtain preliminary data that will allow us to define more precisely the research avenues for a subsequent study.

Inclusion Criteria:

• Type 2 diabetes
• Under medication to treat type 2 diabetes
• Aged ≥ 18 years through 70 years

Exclusion Criteria:

• Type 1 diabetes
• Aged <18 years or >70 years
• Abnormal or low blood C-peptide by standard laboratory measurements.
• Have already initiated the change to ketogenic or vegan diet for more than 1 month.
• Pregnant or breastfeeding women