For someone at risk for heart disease, the most important dietary changes typically focus on reducing saturated fats, added sugars, and processed foods, while increasing fiber and whole grains. Considering the options provided, the most effective choice would be:
Stop drinking sugary soft drinks and choose more whole grains.
This option emphasizes reducing added sugars, which can contribute to obesity and heart disease, and encourages the consumption of whole grains, which are beneficial for heart health due to their high fiber content.