Here's how it happens. You sit down to eat but you did not drink any water before that. Digestion requires a lot of water but because before the meal you did not drink any it is provided by the cells in the body, including from the blood. Onto the food in the stomach must be poured water in order to be fragmented the proteins to their building blocks - the amino acids. Water is needed in the intestine to be processed the components of the food and to be transported further on to the liver. In the liver specialized cells continue processing the digested intestinal nutrients. The liver also needs water in order to process the ingredients of the food. The blood which is provided with new building substances and has the required composition is pumped into the right heart ventricle. Simultaneously in the right half of the heart by the lymph system enter some of the fatty ingredients. Then this blood is pumped to the lungs to be oxygenated and for exchanging of the dissolved gases in it. In the lungs the blood is further dehydrated by the addition of oxygen - by vapour exhalation which in winter appear as steam from our breath. Then highly concentrated blood passes from the lungs into the left ventricle and is pumped into the arterial circulation. Namely thereof are fed coronary arteries, those that supply the heart with oxygen. From there the brain is supplied as well.
Did you notice that until it reaches the coronary arteries of the heart the blood became "dry" and concentrated. Namely in this form it has the greatest potential for thrombus formation. Now let us also add two more circumstances. By dehydration and harmful lifestyle people "fill" their arteries with cholesterol plaques and by smoking cause vasospasm (reflex reducing the inside cross section of the blood vessels) in each puff of the cigarette. Do you follow carefully my thought! Are you beginning to assemble the picture? No? Let me finish then. When collecting these three ominous factors - highly condensed blood, atherosclerotic plaques and vascular spasm, the heart literally aims to explode! Because this is impossible something else happens. Over time, due to the thick dehydrated blood, plaques and smoking, increases the blood pressure, coronary arteries become clogged and all this leads to heart rhythm disorders such as high heart rate and finally to ... infarction or stroke.
For this reason, the most common form of heart attack is the left ventricular one ("front") because the thickest blood is one that comes from the lungs into the left ventricle. You don't have to be overweight to "fill" your arteries with cholesterol plaques. You may even look skinny but it is enough to not drink enough water, to smoke cigarettes and to not eat fruits and especially green leafy vegetables. Then at the latest by your fiftieth anniversary you will experience infarction and/or stroke.