Extra virgin olive oil (EVOO) is known for its cardiovascular effects and its effect on glucose lowering. However, the effects of EVOO on the blood glucose of Type 2 Diabetes Mellitus Filipino patients has not been studied. The investigators aimed to determine whether a significant difference exists in meals containing EVOO versus meals without EVOO among Type 2 Diabetes Mellitus patients.

Thirteen patients were included in this randomized controlled cross-over trial. They were randomized to receive a meal with or without EVOO followed by a one week wash out period, where they were given the other intervention. The primary outcome is the trans-meal blood glucose, which is calculated as the percent change in 2-hour postprandial blood glucose.

During their first visit, the participants were oriented on the conduct of the study. They were advised to be compliant with their medications throughout the duration of the trial.

On their second visit, participants were asked to do a six to eight-hour overnight fast, and their fasting blood sugar was drawn. Serum samples were analyzed through the hexokinase method. The participants were then randomly allocated (first allocation) by the dietician through a coin toss to receive a standard breakfast without EVOO or a meal admixed with one tablespoon of EVOO. The standard meals were labeled with serial numbers, and both the participants and the investigator were blinded to the intervention. The meals were consumed steadily in 15 to 20 minutes, after which, the food containers were collected to ensure its full consumption. Breakfast was chosen in order to avoid a second meal bias. The participants were asked to sit in the waiting area of the laboratory until the 2-hour postprandial blood sugar was due to be drawn.

After a one-week washout period, the participants were asked to come back for a cross over to the other treatment arm (second allocation). The participants were given the same test meal to ensure that that the glycemic index of the food remained constant.

Inclusion Criteria:

1. patients aged 30-65 years old
2. diagnosed with Type 2 Diabetes Mellitus
3. body mass index under the overweight or obese class I category (by Asia Pacific guidelines)

Exclusion Criteria:

1. pregnant patients
2. patients with history of frequent hypoglycemic episodes
3. those at high risk of developing ketoacidosis and hyperglycemic hyperosmolar syndrome
4. those with identified acute stress during the study (illness, fever, trauma leading to hospitalization)
5. current intake of steroids
6. olive oil allergy or intolerance
7. digestive disorders

Data gathered from this study were treated in conformance with the principles of confidentiality, codes were used in data collection forms and documents accessible only by the primary investigator. Explicit consent for sharing individual participant data was not taken.