Evidence is accumulating that poor quality food is a major cause of obesity, diabetes, cancer and cardiovascular disease. Generally, poor quality food does not supply the required nutrients for optimal health or contains substances that causes disease or metabolic abnormalities. Foods containing high quantities of sugar, refined oils, artificial trans fats and processed grains could all be classed as poor quality foods. In contrast a high quality foods contain nutrients or chemicals that are beneficial to the health and prevent disease. Foods that have little food processing such as whole grains, fruits, vegetables, legumes, oily fish and extra virgin olive oil are high quality foods because research has shown that they are beneficial to the health. The Mediterranean diet contains mainly unprocessed high quality foods and has been shown in a large body of research to prevent disease and aid weight control.
Poverty is often associated with poor quality nutrition, but the reasons for this are not straightforward. Evidence form epidemiological studies suggests that rural communities in developing countries generally have higher levels of infectious diseases, but lower levels of lifestyle disease, when compared to Western nations. This difference is likely due to lower levels of protein in the diets which adversely affects the immune system. Animal protein foods tend to be more expensive and so poor rural populations in developing countries attain higher percentages of their protein from vegetable sources. In contrast, the low quality nutrition found amongst the poorest populations of Western nations, usually those in inner cities, is likely due to lower levels of education regarding food selection and nutrition in combination with the availability of convenience food and fast food restaurants.
Because cost might be a limiting factor in buying higher quality foods, researchers1 have investigated the financial impact of adopting the Mediterranean diet. In Canada, 72 women were educated about the benefits of the Mediterranean diet by a dietician, and were given a frequent food questionnaire at baseline and weeks 6, 12 and 24. The researchers calculated the costs of the foods by using a current price lists against the foods listed in the frequent food questionnaire. Adherence to the Mediterranean diet led to increases in costs related to vegetables, fruits, legumes, nuts, seeds, olive oil, whole grains, poultry and fish. However these costs were offset by the reduction in costs relating to red meat, refined grains, desserts, sweets and fast food. Overall there was no increased cost in adopting the Mediterranean, and the energy density of the food was reduced at week 12, suggesting that the diet may aid weight loss.
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