If the person is not on intravenous glucose administration and other nutrients like pre digested proteins or amino acids, fat emulsions, vitamins and minerals are not supplied through the parenteral route or intravenously to the patient, he is more likely to suffer from severe malnutrition by subsisting on a diet of ice creams, toast and hot chocolate alone. A poor diet definitely leads to multiple nutrient deficiencies including vitamins, minerals and proteins. Protein deficiency leads to loss of muscle mass. It is accelerated especially if a person is immobile or bed ridden. Lack of mobility also causes calcium losses from the bones making them weak. Hope this answers your query.