Why our body needs calcium
Calcium is a mineral that is stored in the bones. Nearly all the calcium in the body is stored in bone tissue. But a small amount (around 1%) circulates dissolved in the blood and other body fluids, or is inside our cells. This is needed for

If your blood calcium level gets too high or too low it can be dangerous. Having too much calcium in the blood is called hypercalcaemia (pronounced hyper-kal-seem-ia). Hypercalcaemia in cancer can be a serious problem for some people. Not having enough calcium is called hypocalcaemia (hypo-kal-seem-ia).

Where the body get its calcium from

Our diet gives us calcium. The foods highest in calcium include

Our bodies absorb calcium from the food we eat through the lining of the bowel. The calcium is stored in the bones. The body controls the amount of calcium in the bloodstream very carefully. When blood levels of calcium fall too low, the bones release calcium into the blood. The amount of calcium absorbed from food in the bowel also increases. And the kidneys get rid of less calcium through the urine. If blood levels of calcium get too high, the opposite happens.

There are 3 hormones in the body that play an important role in this complicated control system. These are
    Parathyroid hormone (PTH) – made by the parathyroid glands
    Vitamin D
    Calcitonin

These hormones help to keep the correct balance of calcium in the blood.
If this balance is upset, the amount of calcium in our blood can get too high (hypercalcaemia) and cause serious problems.

The main causes of hypercalcaemia are

 It takes more than just a diet to keep your weight in check. 

A good weight-loss programme must have behaviour modification for long-term success. Regaining weight goes beyond just going back to old eating habits. As you drop weight, your body triggers mechanisms which encourage regain. There are several reasons why dieters can’t keep their weight off. 

 Many studies have shown that when overweight or obese people lose weight, their bodies undergo hormonal changes that increase hunger and satiety. Leptin is a hormone produced by fat cells, which regulates appetite.

 It tells you when to stop eating. When the body loses fat cells, leptin levels decrease. Lowered leptin levels trigger hunger and make it harder to feel full with lesser food. Leptin levels can fall by as much as 65-70 per cent when the body loses fat.

These hormonal changes persist and may even become permanent. Other appetite regulating hormones like ghrelin and peptide YY also alter in a way that favours weight gain. 

There may be several other complex mechanisms and hormonal changes which may make you put on weight because of which regain of weight is a strong possibility. The nature of the diet also makes a difference. Following fad diets or going back and forth on diets also triggers the rebound effect. It lowers metabolism by 5-10 per cent, favouring easy regain. 

Then there is the issue changing habits. Without a permanent change in unhealthy patterns of eating and living, it is highly unlikely that weight loss will stick. For example, the benefits of having an early dinner will last only until it is done, and if you go back to eating late, you will begin to put on weight again.