amounts  of  these  nutrients  and  cause  hyper- vitaminosis; death may result in extreme cases. Water-soluble  vitamins,  such  as  B  complex  and ascorbic acid, are not stored to any great extent. Vitamin  supplements  are  usually  not  necessary if   the   diet   includes   a   wide   variety   of   foods. Exceptions may occur in prenatal diets in which iron is low and in patients proven to be deficient in  a  specific  vitamin.  Vitamin  supplements  should be   taken   only   on   a   physician’s   or   dietitian’s recommendation. WATER The body can survive weeks without food, but only days without water. It makes up 70 percent of the body weight and is found in every cell in the  body.  Water  is  the  medium  through  which nutrients  are  transported  from  the  digestive  tract to the cells where they are needed. It is also the medium  through  which  the  by-products  of  cell metabolism  are  removed.  Water  also  serves  as  the medium  in  which  the  chemical  processes  of  life take  place. Fluid  needs  are  increased  with sweating, vomiting, diarrhea, high protein diets, and  hot  environments.  Water  is  normally  taken into the body in beverages, soups, and in the form of  solid  foods.  An  insufficient  intake  may  cause constipation,   loss   of   weight,   abnormal   body temperature, and dehydration leading to ketosis. GUIDE  TO  GOOD  EATING Calculating   therapeutic   diets   can   be   com- plicated  and  is  best  left  to  dietitians.  For  daily living, there is a simple, practical plan, based upon the  classification  of  foods  into  groups  according to  the  nutrient  content. It  is  now  common  practice  for  dietitians  or dietary  kitchens  to  select  foods  for  diets  on  the basis of food groups. See figure 3-1 for the Guide to  Good  Eating  food  groups.  They  are  classified according  to  their  nutritional  value  and  the number  of  servings day.   This   figure and  effective  guide diets. that  should  be  eaten  each can   serve   as   a   simple in  planning  or  evaluating DIETS The appetite of the patient requires catering to,  as  patients  tend  to  be  more  fastidious  when sick.  In  some  disease  states,  such  as  cancer, patients  experience  marked  taste  changes.  Because of the importance of the nutritional elements in feeding  the  sick,  try  to  carry  out  the  patient’s wishes  whenever  possible.  A  tactful  and  observant hospital  corpsman  will  be  most  helpful  to  the physician  and  dietitian  in  carrying  out  the  dietary regimen,  You  must  be  aware  of  what  comprises a  well-balanced  diet  and  should  be  able  to recognize  when  dietary  adjustments  need  to  be made  in  special  situations.  This  is  important  to meet  the  changing  needs  of  the  diseased  body’s ability  to  make  use  of  foods. The  patient  should  be  made  to  feel  that  the utmost cleanliness and care have been observed. The  patient’s  face  and  hands  should  be  cleaned before  food  is  served,  and  the  lips  and  teeth cleaned before and after the meal. If the mouth is  dry,  it  should  be  moistened  periodically. When  special  or  modified  diets  are  ordered, check  the  contents  of  the  tray  with  the  written orders.  An  error  in  serving  a  special  diet may   cause   discomfort,   serious  illness,  or  even death. OBJECTIVES OF DIET THERAPY The  dietary  objectives  are: l  To  increase  or  decrease  body  weight l  To  rest  a  particular  organ;  e.g.  to  limit cholecystagogues  in  preventing  gallbladder  con- traction .  To  adjust  the  diet  to  the  body’s  ability  to use  certain  foods l   To   produce   some   specific   effect   as a  remedy;  e.g.  to  regulate  blood  sugar  in  dia- betes .  To  overcome  deficiencies  by  the  addition of  food  rich  in  some  necessary  element;  e.g.  to supplement  the  diet  with  iron  in  treating macrocytic  anemia .  To  provide  ease  of  digestion  by  omitting irritating substances, such as fiber, condiments, or  fried  foods Diets used in the treatment of disease are often spoken of by names that show a special composi- tion and often indicate the purpose for which the diet is intended. 3-4