There are many thousands of miles of blood vessels in the human body and every inch becomes a little swollen/distended/dilated if the blood vessels become weakened by dieting/'slimming'/fasting or relaxed by certain prescription drugs, e.g. tricyclic anti-depressants like amitriptyline, cortico-steroids, oestrogen-rich medications, anti-psychotics, certain painkillers, etc. - This means in effect that because of fluid retention with sodium and the water it attracts to itself, increased blood volume will cause you to gain excess weight.
When I googled to find how many miles I found different estimates - 60,000, 62,000 and 100,ooo miles. - You may possibly find other estimates; but it's clearly a helluva lot!
When people whose blood vessels are weaker than the norm eat salt, the result is weight gain and obesity (because of excess sodium and water held in the blood vessels and elsewhere). This condition is also known as sodium retention, water retention, fluid retention, salt sensitivity or oedema. If these people reduce their salt intake they lose some of the excess sodium and water, and so lose weight, and if they eat plenty of fresh fruit and vegetables they lose weight faster, because the potassium in the fruit and vegetables displaces some of the excess sodium from the body.
Lose weight, reduce your risk of most cancers, high blood pressure, type 2 diabetes, stroke, heart disease, heart attack, vascular dementia, osteopenia, osteoporosis, hypercholesterolaemia, depression, liver and kidney problems, and improve your health in many other ways without drugs or expense by eating less salt! - Try it! - You will feel so much better!
Read my Mensa article on Obesity and the Salt Connection
Children and Obesity
And see Sodium in food
Associated health conditions
and FAT RETENTION