BMR study is important for Calculation of caloric requirements of an individual for prescribing a diet of adequate calorific value and planning nutrition for individuals, communities and populations at large.

For total energy requirement Specific dynamic action and physical activity levels are the important attributes of Basal Energy Expenditure.

Specific Dynamic Action Also known as thermogenic effect of food. Increased heat production following the intake of food. Energy expenditure on digestion and absorption. Trapped from energy stores Actual energy from food is less than theoretical content Activation energy needed for a chemical reaction and is to be supplied initially

EXAMPLE A person takes 250 grams of carbohydrates Should produce 250 x4 =1000 Kcal 10% needed for activation = 100 kcal Actual energy available = 900 Kcal If requirement is really =1000 Kcal Then the person should actually take an amount capable of providing 1100 Kcal i.e. 275 grams

SDA Values Carbohydrates 05% Protiens 30% Fats 15% Mixed Diet 10%

Physical Activity Level (PAL) Energy required in kcal/hour (over and above BMR) 1. Eating 28 2. Writing 30 3. Driving a car 63 4. Typing at high speed 100 5. Walking 140 6. Cycling 175 7. Running 490 8. Swimming 550

Energy Requirement and Occupation Type of activity Occupation Light Sedentary Work Office workers, lawyers, accountants, doctors, teachers, architects, shop workers Moderate Work Students, industry workers, farm workers, housewives without mechanical appliances Active heavy Work Agricultural workers, miners, unskilled laborers, athletes, factory workers Very Heavy Work Lumber jacks, blacksmiths, and construction workers BMR+30 % BMR+40 % BMR +50% BMR+70 %

Calculation for energy requirement for a 55 kg person doing moderate work For BMR = 24 x 55 kg = 1320 kcal + For activity = 40% of BMR= 528 kcal Subtotal = 1320 + 528 = 1848 kcal + Need for SDA= 1848 x 10% = 185 kcal Total = 1848 + 185 = 2033 kcal Round to nearest multiple of 50 = 2050 kcal

Proximate Principles Carbohydrates Fat Proteins Minerals Vitamins Additional requirements for growth pregnancy lactation and convalescence are to be provided in the food.

Respiratory Quotient When food is oxidized, whether in an open system or closed biological system, oxygen is consumed and CO2 produced. Volume of CO2 produced Volume of O2 consumed = RQ Ratio in steady state / Unit time

Carbohydrates are completely oxidized and the volume of O2 used is equal to CO2 produced C6H12O6 + 6O2  6CO2 + 6H2O RQ = 6CO2 6O2 = 1

Fats C57H104O6 + 80 O2  57 CO2 + 52 H2O RQ = 57 = 0.71 80 Other fats have RQ  0.70

Using specialized technique the RQ is found to be 0.82 Proteins RQ of proteins is a little complex to determine as it contain N & S in addition to C, H, O. Using specialized technique the RQ is found to be 0.82

Alcohol C2O5OH + 3O2  2CO2 + 3H2O RQ = 2/3 = 0.67

Human Use normally mix type of food RQ of an intact person naturally will be the sum of RQ of all the three major type of food. Carbohydrates Fats Proteins

Ordinary mixed diet RQ = 0.85 Postabsorptive State No food being consumed in preceding 12 – 14 hours RQ = 0.82

When diet is rich in Carbohydrates the RQ will be more close to one i When diet is rich in Carbohydrates the RQ will be more close to one i.e. High More fats = Lower RQ

Methods for determination of RQ of Man Two method Open Circuit Closed Circuit

Open Circuit Made to breath in a specially designed bag called Douglas Bag for few minutes Volume of Breathed air is measured in a gasometer Subjected to gas analyzer Where CO2 is absorbed by KOH Original volume of gas is reduced

Open Circuit Concentration of CO2 is calculated Remaining gas is allowed to react with alkaline pyrogalate which absorb O2 O2 in the expired is found out RQ is calculated volume of CO2 volume of O2

Remember that when rate of utilization of fat increases in relation to carbohydrates, RQ falls. Commonly seen in Diabetes mellitus Utilization of carbohydrates increases RQ

Energy requirement of a normal person While calculating we should consider the energy required for Maintenance of BMR Thermogenic effect of food (SDA) Extra energy expenditure for PA

Remember that when rate of utilization of fat increases in relation to carbohydrates, RQ falls. Commonly seen in Diabetes mellitus Utilization of carbohydrates increases RQ

BALANCED DIET

BALANCED DIET Diet which provides all the five basic nutrients in a quantity which ensures healthy life is known as Balanced diet. These are : Carbohydrates Fats Proteins Vitamins and Minerals

The Food Pyramid

The Food Pyramid

Nutrient Pool

Water Water of course is another important essential nutrient required for normal metabolism of all the essential five.

NUTRITIONAL IMPORTANCE OF CARBOHYDRATES

Polysaccharides and Disaccharides Cannot be utilized until digested to the monosaccharide stage. When introduced directly into blood stream, they act as foreign bodies and are excreted by the kidneys.

Role of carbohydrates in diet Glucose, fructose, galactose and to a minor degree, manose / Precursors are available to the body as energy source. Pentoses in foods seem to be of limited nutritional value and form a very small fraction of the total carbohydrate intake of diet. Ribose, deoxyribose are required for nucleic acid synthesis and are obtained from HMP-Shunt.

Requirement of carbohydrates in diet 55 to 65% of the total food calories should come from carbohydrates. A moderately active man requiring 3000 C per day, should take about 450 gm carbohydrates daily. But poorer sections of the population derive more than 85% of the food calories from carbohydrates.

Role of carbohydrates in diet Undue restriction of dietary CHO influences both fat and protein metabolism adversely, even if the calorie intake is adequate. Fat mobilization from the depots and utilization is increased Ketogenesis is increased and ketosis may develop.

Role of carbohydrates in diet The effect on protein metabolism is of a specific nature, not shared by other substances, e.g. fats, alcohol and not related to its calorigenic action. This is referred to as "protein sparing action of carbohydrates".

Protein sparing action of CHO Adequate amount of CHO in the diet may reduce the protein requirement due to : Metabolic products of CHO, e.g. oxaloacetate, pyruvates and glutarates provide the C-skeletons for the formation of NEAA through transamination,

Protein sparing action of CHO CHO reduce the need for gluconeogenesis from AA CHO and fats are catabolized for energy and thus spare the proteins from being used for this purpose. Dietary fats may also depress the SDA of proteins.

Action of CHO on Plasma Lipids Replacement of a low or moderate CHO diet by a high CHO diet may produce temporary rise in plasma TG and VLDL and temporary reduction in blood cholesterol. Substitution of starch by fructose or sucrose in the diet may also increase plasma TG by increasing lipogenesis from fructose.

B-vitamins Requirements With diets rich in CHO, the requirements for vitamins, particularly thiamine (vit B1) increases because of the essential role of these in carbohydrate metabolism.

Role of Cellulose Celluloses are polysaccharides found in plants. They are indigestible by human beings as there is no enzyme in our GI tract which can split  l -4 linkage.

Role of Cellulose Celluloses in diet contribute bulk to the intestinal contents, and therefore, in normal amounts promote intestinal motility, i.e. increases peristalsis and removes constipation. When present in excess, they may be irritating to intestinal mucous membrane, producing diarrhea or a spastic type of constipation.

Health Benefits of Fiber Adds bulk to stool / improves peristalsis Decreased transit time = decreased exposure to toxins Weight control Helps prevent Colon cancer Hernia Ulcerative colitis Hemorrhoids

Health Benefits of Fiber Helps control blood sugar Helps lower cholesterol Helps prevent diverticulitis How Much? 25–35 g per day from food No more than 50 g

Excessive intake of carbohydrates in diet: Ingestion of excessive amounts, specially in infants, may occasionally produce intestinal disturbances due to irritation induced by products of bacterial fermentation. There is some evidence in experimental animal (rats) that continued ingestion of super tolerance amounts of galactose, may result in the formation of cataracts. A similar phenomenon has been suggested as possibly occurring in man.

Excessive intake of carbohydrates in diet: In children, in the presence of hepatic functional impairment, in which the conversion of galactose to glucose (or glycogen) may be impaired, with consequent elevation of blood galactose level. The incidence of cataract is relatively high also in uncontrolled diabetes mellitus, a phenomenon presumably related to persistently elevated blood glucose concentration and altered metabolism.

Recommendation for Simple Sugar Intake Low nutrient density No more than 10% of total kcal / day Average U.S. intake: 16% of total kcal/day Added to food and beverages during processing

High-Sugar Diets Calories adding to excess Obesity Dental caries

Lactose Intolerance Enzyme (lactase) is needed to break down lactose. Reduction in this enzyme, leads to diarrhea, bloating, flatulence when dairy products are consumed

What to Do If , Lactose Intolerant Determine amount one can tolerate Eat dairy with fat Cheese is usually tolerated well Yogurt is usually tolerated well Use Lact-Aide Use soya or rice-based dairy substitute products

Dietary Sources Of Carbohydrates Major dietary polysaccharide is starch, which is digested by amylase to maltose and then hydrolyzed to glucose. Starch is the major source of fuel for most organs and tissues. Excess is converted to fat and stored. Cooking makes starch more soluble and accessible to digestive enzymes.

DIETARY SOURCES Cereals, pulses and tubers Rice is also a rich source of carbohydrates along with vitamin B1

Carbohydrate Content of Common Food Cane sugar 100% Rice 80% Honey 80% Wheat 70 – 80% Cakes 55 – 65% Bread 50 – 60% Potatoes 25%

Sucrose Cane sugar is mainly used as a sweetening agent. In young children high intake of sucrose and sucrose-rich food items predispose to the development of dental caries. Sucrose is easily fermented by the bacteria present in dental plaque, which would damage the enamel and lead to caries (tooth decay).

In adults Consumption of large quantities of refined sugars is not advisable since they tend to lead to a sudden rise in blood glucose level. This will also lead to excessive caloric intake. Sucrose consumption also results in increased levels of plasma lipids.

While prescribing diets for diabetic patients and for weight reduction, sucrose should be strictly avoided. Jiggery (Brown sugar from dates) an alternative source of sucrose is beneficial, since it is a good source of iron as well.

Dietary Fiber The unavailable or indigestible carbohydrate in the diet is called dietary fiber. The comparatively high incidence of colon cancers in developed countries, and the low incidence of the same in vegetarian population, pointed to the importance of dietary fiber . Dietary fiber is also necessary to maintain the normal motility of gastro-intestinal tract.

The beneficial effect is more with soluble fiber present in vegetables and only a diet having plenty of vegetables and green leaves will have the desired effect. Dietary fiber requirement is about 30 g/day.

In general, diet rich in fiber improves: Bowel motility prevents constipation decreases reabsorption of bile acids Thus lowering cholesterol level and improves glucose tolerance

Role in weight reduction Fiber rich food is helpful in weight reduction, since it provides a feeling of fullness without consumption of excess calories.

Excessive intake of carbohydrates in diet The incidence of cataract is relatively high also in uncontrolled diabetes mellitus, a phenomenon presumably related to persistently elevated blood glucose concentration and altered metabolism.

Recommendation for Simple Sugar Intake Low nutrient density No more than 10% of total kcal / day Average U.S. intake: 16% of total kcal/day Added to food and beverages during processing

While prescribing diets for diabetic patients and for weight reduction, sucrose should be strictly avoided. Jiggery (Brown sugar from dates) an alternative source of sucrose is beneficial, since it is a good source of iron as well.

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