Processed foods have both salt and sugar together, which makes blood pressure go up more than either one alone because salt adds water and sugar stops your body from getting rid of the salt.

“Now, when we look at the foods that dominate modern diets, what you'll notice is that they don't just contain salt or sugar in isolation. They contain both engineered in specific ratios to maximize palatability and consumption. A single serving of many breakfast cereals or ready meals or fast food items will deliver high sodium and high refined carbs at the same time. That combination isn't accidental. It's deliberate food design and the effect on blood pressure is far worse than either ingredient alone. When you eat processed food, you're getting sodium that immediately expands plasma volume through water retention. And you're getting refined carbs that spike insulin and lock your kidneys into that sodium retention mode. The result is that your blood pressure goes up from the volume load and then it stays up because the hormonal signal to release that sodium never arrives again. You're hitting both pathways simultaneously. The sodium creates the initial pressure rise and the sugar prevents your body from correcting it. That's why ultraprocessed diets are so closely linked to hypertension often more strongly than salt intake alone.”