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How changing diets are affecting health

In this video, Dr Rob Andrew discusses the key components of healthy diets.
Hello. My name is Rob Andrews, Associate Professor of Diabetes in the Exeter Medical School. I’m going to tell you what constitutes a healthy diet, and some of the consequences of a poor diet. A good diet consists primarily of whole grains, vegetables, fruit, nuts, and pulses. You should consume only moderate amounts of low fat dairy foods and meet. Your consumption of saturated fat should be low, with saturated fat replaced by mono and polyunsaturated vegetable fats and fish oils. Try to avoid trans fatty acids, and keep added sugar to under 10% of your energy intake. There are seven key components of a healthy diet. Carbohydrate and fats are key sources of energy.
Protein helps the body to grow and repair, and is also a source of energy. Vitamins and minerals or micronutrients help the body to work properly. Fiber helps to maintain the digestive system. And water is essential for the body’s chemical reactions. Poor diets are patterns of food intake that do not provide the right balance of nutrients for health. Energy needs are affected by genes, activity levels, health, and environment. If energy intake exceeds the body’s requirements, a person becomes overweight. The prevalence of obesity has increased worldwide, and no longer only occurs in developed countries. When developing countries become urbanized dietary patterns change, which is known as the nutritional transition.
There is an increased consumption of animal fats and foods high in fat and sugar, and low in fiber. There is a reduction of physical activity. This has led to a worldwide rise in the disease linked with obesity, diabetes, coronary heart disease, stroke, and certain cancers, for example, breast, esophageal, and pancreatic cancer. We also see the paradox of what has sometimes become known as the hidden hunger, where the quality of food people eat does not meet their nutritional requirements. Two billion people in the world are meeting or exceeding their calorie and protein needs but are deficient in vitamins or minerals.
In China, for example, weight gain has increased fastest amongst low income and rural adults, due to a shift towards diets dominated by cheap refined starches, vegetable oils, and cheap and processed meats. These energy dense diets are low in fiber, vegetables, and fruit, and deficient in micronutrients. Individuals living on these diets can simultaneously be overweight, and at risk of poor health due to deficiencies. This situation is worse if an individual experienced chronic undernutrition early in life. Excessive weight gain in people affected by stunting further increases the risk of diabetes, cardiovascular disease, and certain cancers. Fruits and vegetables are high in fiber, vitamins, phytonutrients, and potassium, and low in energy.
But low fruit and vegetable consumption is estimated to contribute to 2.6 million deaths, 11% of strokes, and 31% of coronary heart disease. The World Health Organization recommends consuming at least 400 grams of fruit and vegetables per day to reduce the risk of developing cardiovascular disease, diabetes, and obesity, as well as avoiding micronutrient deficiencies. Each additional serving per day is associated with a 6% reduction in stroke, a 4% lower risk of fatal coronary heart disease, and a reduction in overall cancer risk. In the UK, consumption is on average only 2.8 servings per day. People’s reason for low consumption ranged from disliking vegetables and fruit, not knowing how to prepare them, lack of time, and lack of availability.
Worldwide, though, the greatest barrier is cost.
Meat and dairy products are high in saturated fats. Diets high in saturated fats are strongly associated with coronary heart disease, perhaps because they raise cholesterol levels. Trans fatty acid, produced by the partial hydrogenation of vegetable oils, also raise cholesterol levels. Meats preserved by smoking, salting or the addition of nitrates or nitrites increase the risk of colorectal cancer. Another risk factor in colorectal cancer is the high consumption of red meat, probably due to the HCAs and the PAHs produced by the high temperature cooking of red meat. So as we can see, poor diets pose a variety of health and disease risks.
Diets high in red and processed meats, high fat dairy foods, processed foods, and sugar are associated with diabetes, cardiovascular disease, and cancers. Diets rich in fiber, fruit, and vegetables are associated with reduced risk of these diseases.

In this video, Dr Rob Andrew discusses the key components of healthy diets, describes what is the effect of urbanisation on people’s health and highlights the importance of eating five portions of fruits and vegetables daily.

In the following article we will look at recommendations for healthy and sustainable diets in more detail.

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Future Food: Sustainable Food Systems for the 21st Century

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