Unhealthy diets

An unhealthy diet is a major risk factor for a number of chronic diseases including: high blood pressure, diabetes, abnormal blood lipids, overweight/obesity, cardiovascular diseases, and cancer.^[25]

The WHO estimates that 2.7 million deaths are attributable to a diet low in fruits and vegetables every year.^[25] Globally it is estimated to cause about 19% of gastrointestinal cancer, 31% of ischaemic heart disease, and 11% of strokes,^[2] thus making it one of the leading preventable causes of death worldwide.^[26]

Fad diets[edit]

Main article: Food faddism

Fad diet usually refers to idiosyncratic diets and eating patterns.^[27] They are diets that claim to promote weight loss or treat obesity by various mechanisms,^[28] provide little to no scientific reasoning behind their purported health benefits, and have little or no proof to support them.

Public health[edit]

Fears of high cholesterol were frequently voiced up until the mid-1990s. However, more recent research has shown that the distinction between high- and low-density lipoprotein('good' and 'bad' cholesterol, respectively) must be addressed when speaking of the potential ill effects of cholesterol. Different types of dietary fat have different effects on blood levels of cholesterol. For example, polyunsaturated fats tend to decrease both types of cholesterol; monounsaturated fats tend to lower LDL and raise HDL; saturated fats tend to either raise HDL, or raise both HDL and LDL;^[29][30] and trans fat tend to raise LDL and lower HDL.

While dietary cholesterol is only found in animal products such as meat, eggs, and dairy, studies have not found a link between eating cholesterol and blood levels of cholesterol.^[31]

Vending machines in particular have come under fire as being avenues of entry into schools for junk food promoters. However, there is little in the way of regulation and it is difficult for most people to properly analyze the real merits of a company referring to itself as "healthy." Recently, the United Kingdom removed the rights for McDonald's to advertise its products, as the majority of the foods that were seen have low nutrient values and high fat counts were aimed at children under the guise of the "Happy Meal"^{[citation needed]}. The British Heart Foundation released its own government-funded advertisements, labeled "Food4Thought", which were targeted at children and adults displaying the gory nature of how fast food is generally constituted.

Cultural and psychological factors[edit]

From a psychological and cultural perspective, a healthier diet may be difficult to achieve for people with poor eating habits.^[32] This may be due to tastes acquired in childhood and preferences for sugary, salty and/or fatty foods.^[33]