Diet, specifically the type of food eaten, can cause blood pressure to increase or decrease. A rise in insulin causes blood pressure to rise temporarily after eating and is a natural reaction to certain types of foods, according to Mercola.
Fructose and caffeine are both capable of causing blood pressure to increase, says Mercola.
Some people who already have high blood pressure are sensitive to salt, and this can cause a spike in blood pressure, according to WebMD. Stress can also cause a blood pressure increase, as well as insufficient amounts of potassium, calcium and magnesium in the diet.