Obesity is not the only nutrition-related cause of disease onset and progression. Too much or too little of certain nutrients can also contribute to health issues. For instance, a lack of calcium in your diet can predispose you to developing osteoporosis, or weakening of your bones, while too much saturated fat can cause cardiovascular disease, and too few fruits and vegetables in your nutrition plan is associated with an increased incidence of cancer. Consuming foods from a wide variety of sources helps ensure your body has the nutrients it needs to avoid these health problems.