(C) 13[?]Body Mass Index (BMI) or Quetelet index is a value derived from the mass (weight) and height of an individual.BMI is the body mass divided by the square of the body height, & is universally expressed in units of kg/m2, resulting from mass in kilograms & height in meters.BMI is universally expressed in kg/m2, resulting from mass in kilograms and height in meters.If pounds & inches are used, a conversion factor of 703(kg/m2)/(lb/in2) must be applied.BMI is used informally, the units are usually omitted.BMI =Masskg /Heightm2 =Masslb /Heigh-tin2 X703BMI provides a simple numeric measure of a person's thickness or thinness, allowing health professionals to discuss weight problems more objectively with their patients.BMI was designed to be used as a simple means of classifying average sedentary (physically inactive) populations, with an average body composition.Current value recommendations are as follow: a BMI from 18.5 up to 24.9kg/m2 may indicate optimal weight, a BMI lower than 18.5 suggests the person is underweight, a number from 25 up to 30 may indicate the person is overweight, and a number from 30 upwards suggests the person is obese.Athletes (e.g. gymnasts, basketball & soccer players) have a high muscle to fat ratio and may have a BMI thatis misleadingly high relative to their body fat percentage.Although, BMI of 30t is an indication of obesity, it is not a direct measure of adipose tissue fat mass.One of the refractory mechanisms that maintain body mass in Leptin, identified by Jeffrey Friedman in 1994.A blood borne factor; 17,kDa protein made exclusively in adipocytes.Deficiency of Leptin or Mutation in Leptin gene leads to obesity.Deficiency of Leptin receptors leads to Leptin resistant obesityLeptin:Modulates specific neurons in the arcuate nucleus of hypothalamus that control feeding behaviour - as a long term regulator.Promotes fuel utilization.NUTRITIONAL STATUSThere is no gold standard for diagnosis of malnutritionThere are several quick assessment toolsBody Mass Index (BMI) & Nutritional StatusBMINutritional Status*. >30kg/m2Obese*. >25-30kg/m2Overweight*. 20-25kg/m2Normal*. <18.5kg/m2Moderate malnutrition*. <16kg/m2Severe malnutrition*. <13kg/m2Lethal in males*. <11kg/m2Lethal in femalesUNDERWEIGHTBeing underweight (BMI<19) can be dangerous, especially in age.BMI value considered lethal for men is 13, whereas females withstand and survive even at lower BMI rate up to 11.Factors that cause underweight include genetics, eating disorders, depression, digestive problems, and thyroid conditions.As people get older, it becomes harder to heal if the body doesn't have some fat reserves.Especially in older women, being very thin can be associated with osteoporosis and brittle bones.