Adolescents have greater needs for energy, protein, Ca, P, Fe, Zn and vitamin A because of the rapid growth during this stage.15 Besides catering for the higher protein and energy needs, care should be taken that the diet includes green leafy vegetables or other foods rich in calcium. Supplementation to augment supplies of B-12 and zinc are also recommended for this stage.
Energy requirements
Energy requirements depend largely on lifestyle, but tend to vary between 1 800 calories per day for a sedentary to mildly active individual to in excess of 3 500 calories per day for intensely active individuals. Vegan vegetarians need to consume a greater proportion of high energy foods such as grains, legumes, seeds, nuts and energy rich fruits and vegetables than do non-vegans. Non-vegan vegetarians tend to have a higher fat intake than vegans, because of the consumption of dairy product and eggs, and this makes it easier for them to meet their energy demands. The consumption of these animal fats and proteins, however puts them in a higher risk category in terms of degenerative diseases. Normally, the natural cravings of the system will ensure that sufficient energy-rich foods are consumed, particularly by active people, but when there are changes in lifestyle it may be useful to calculate what the body’s needs are in order to put one’s mind at rest.
To calculate the daily number of calories required for one’s particular lifestyle, it is necessary to know what one’s BMR (Basal Metabolic Rate) is, and the multiple of BMR associated with a particular lifestyle. The BMR is the energy expended while lying awake but completely still and the multiple of BMR is the factor by which BMR must be multiplied in order to account for other daily activities such as walking etc. The “Dunn Clinical Nutrition Centre” in Cambridge UK, recently collated measurements from all over the world in order to estimate the multiple of BMR associated with various activities. These are summarised in table 5.3., and the formulas for calculating the BMR are presented in table 5.4.
Table 5.3. The multiple of BMR associated with various activities.( From reference 26)
Table 5.4. Equations for calculating BMR. (From reference 26)
Using the data above, it is now possible to calculate the total energy needs per day. First calculate the BMR using the formulae in table 5.5 and multiply it by the appropriate “multiple of BMR” from table 5.4.
Example:
A housewife aged 35 and weighing 55 kilograms
BMR = (8.3 x 55) + 846 = 1302
Multiple of BMR for a housewife = 1.8
Total calories required = 1302 x 1.8 = 2345
To convert to kilojoules, multiply this figure by 4.2
HEALTH ASPECTS OF THE VEGETARIAN DIET
Vegetarians have a lower incidence of degenerative diseases than do non-vegetarians, and as the foundations for many of these diseases are already laid in childhood,27 it is prudent to establish good eating habits early on in life.
The vegetarian lifestyle has often been met with suspicion, if not outright scorn, but in recent times the positive effects of a vegetarian lifestyle have come to be recognized. More research has been done on vegetarianism in the past two decades than in the entire history of the human race, and thorough reviews of the relevant literature exist.28 Of all the vegetarian groups studied, the World Health Organization made special mention of the Seventh-day Adventists as they, on different occasions have received special notice because of their low number of heart attacks, cancer and other diseases related to lifestyle.29 Seventh-day Adventists generally, though not exclusively, follow a vegetarian lifestyle, with all types of vegetarianism represented. They also avoid alcohol and smoking, which makes them an ideal study group and probably accounts for the fact that mortality rates for lung cancer are only 20% of those of the general populace, whereas the low figures for throat cancer (5%), bladder cancer (28%) and cirrhosis of the liver (13%) are probably also as a consequence of the avoidance of these commodities. Mortality is also down for most other diseases, and with the exception of breast cancer (72%), digestive tract cancer (65%), ovarian cancer (61%) and heart attacks and angina
(55%), the mortality for most other diseases is less than 50% of that of the general populace.5,28,30,31,32,33,34,35,36
In view of the strong correlation between the consumption of dairy products and eggs with some of the types of cancers listed above, it is not surprising, that those who’s lifestyles where more vegetarian, or tended towards the vegan lifestyle, had lower age specific mortality rates than those whose lifestyles tended towards omnivorous diets.37 Numerous studies, on vegetarianism in general, have shown that it is not only the longevity of life that is extended in vegetarians, but that the quality of life is also improved. This is because many of the common diseases that plague mankind are less