Along with a balanced diet, weight-bearing exercise promotes bone mineral density. Ruben's body-builder diet would be unhealthy for his bones over the long term because it is .

it is lacking adequate levels of Vitamin D and Calcium.

Explanation:Vitamin D deficiency can lead to loss of bone density, which is a contributory factor to osteoporosis and broken bones.

Severe vitamin D deficiency can also lead to other diseases. Vitamin D deficiency leads to osteomalacia. Osteomalacia which causes weak bones, bone pain, and muscle weakness. Because Reuben's body builder diet lacks Vitamin D, it can cause fractures and even osteoporosis over when used for a long time especially without trying to make amends for the deficient Vitamin D.

inadequate in vitamin D and excessive in calcium

Explanation:

Vitamin D plays a significant role in the regulation of calcium and maintenance of phosphorus levels in the blood. These factors are vital for maintaining healthy bones. People need vitamin D to allow the intestines to stimulate and absorb calcium and reclaim calcium that the kidneys would otherwise excrete.

Foods that provide vitamin D include:fatty fish, like tuna, mackerel, and salmon.

Foods fortified with vitamin D, like some dairy products, orange juice, soy milk, and cereals.

Beef liver.

Cheese.

Egg yolks.