Some negative aspects to low-fat diets include the encouragement of consumption of harmful foods, the raising of triglycerides, the avoidance of healthy foods and the lowering of HDL, or "good," cholesterol. Further, low-fat diets can lower testosterone levels and may lead to heart disease.
Although manufacturers may have people's best intentions in mind, there is no denying that products with the fat removed don't taste quite as good. To make up for this, producers often pack these "low-fat" foods with sugar. The result of this is that foods labeled as "low-fat" can contain a harmful amount of sugar. Low-fat diets also promote the consumption of whole wheat and vegetable oil. Whole wheat, which contains gluten, causes an adverse reaction in some people, while vegetable oils are associated with inflammation and heart disease in the long run.
High triglyceride levels can also lead to heart disease. Low-fat diets, which are usually high in carbohydrates, often raise an individual's triglyceride level. As low-fat diets may contain harmful foods, they may also promote the avoidance of healthy ones, like eggs, meat and dairy, which are all excellent sources of necessary vitamins and minerals. In terms of HDL, or "good," cholesterol, eating fat can actually raise these levels, while studies have shown that a low-fat diet reduces them.