Dietetics and Nutrition in the Mediterranean By Dr. ssa Fabiana Avallone
Obesity and BMI Obesityis a conditionof excess body fat. Obesity is currently defined using body mass index (BMI). BMI is calculated as weight (kg)/ height squared (m²) and is indipendent of sex. BMI is significantly correlated with total body fat content and it’s now internationally accepted as a means of identifying overweight and obesity. The risks of developing type 2 diabetes, heart disease and cancer all increase as BMI increases, with the lower risk generally seen at BMIs of 22 to 25 kg/m². Mortality increases gradually above a BMI to 25 kg/m².
Obesity: epidemiology Obesityis a conditionof excess body fat. For the first time in history, most US adults are overweight or obese, and as such they have substantially increased morbidity and mortality from hypertension, stroke, coronary artery disease, dyslipidemia, type 2 diabetes, sleep apnea and numerous other conditions. Higher BMI also increases all-cause mortality.
Obesity: epidemiology According to NHANES 1999-2000 (National Health and Nutrition Examination Surveys), an estimated 64% of persons in the United States are overweight (BMI 25-30) or obese (BMI ≥30); that is 8% higher than 1988-1994 and 17% higher than in 1971-1974. Among adults 20 to 74 years old, the estimated prevalence of obesity (BMI ≥30) doubled between NHANES 1976-1980 AND NHANES 1999-2000 from abaut15 to 31%. The consequences for the health care system are important for the obesity-related comorbidities.
Obesityas a disorderofenergybalance Obesity can develop only as a result of an imbalance between energy intake and energy expenditure. High energy intake leads to obesity only if it is not matched by high energy expenditure, and low energy expenditure leads to obesity only if it is not matched by low energy intake. When intake is lower than expenditure, negative energy balance occurs, and body energy stores are reduced. When energy intake exceeds expenditure, positive energy balance occurs, and body energy stores are increased.
Obesityas a disorderofenergybalance COMPONENTS OF ENERGY BALANCE (positive or negative) Energy intake We take in energy in the foods we eat. The major macronutrient sources of dietary energy are fat, carbohydrates, protein and alchool. Energy expenditure Resting Energy Expenditure Physical Activity Energy Expenditure Thermic Effect of Food
Obesityas a disorderofenergybalance Energy expenditure Total energy expenditure (TEE) is the sum of resting energy expenditure, thermic effect of food and physical activity-related energy expenditure. Resting Energy Expenditure REE The majority of human energy expenditure is through the body’s metabolism at rest, comprises 60 to 80% of (TEE) in most people. REE is the energy required by the body to maintain basic physiologic functions such as pumping blood, making hormones and maintaining body temperature (in average muscle 25%, brain 20% and liver 22% of REE)
Obesityas a disorderofenergybalance Energy expenditure Total energy expenditure (TEE) is the sum of resting energy expenditure, thermic effect of food and physical activity-related energy expenditure. Physical Activity Energy Expenditure PAEE Is the component of energy expenditure that is most under voluntary control because it is influenced most strongly by the amount of PA. PAEE is the most variable component of energy expenditure and can easily range from 10% of TEE in sedentary persons to 40% of TEE in active persons.
Obesityas a disorderofenergybalance Energy expenditure Total energy expenditure (TEE) is the sum of resting energy expenditure, thermic effect of food and physical activity-related energy expenditure. Thermic Effect of Food TEF TEF is the increase in energy expenditure associated with digestion, absorption and storage of ingested macronutrients, usually 7 to 10% of the total caloric content of the meal. The energy cost of a meal is associated with the macronutrient composition of food consumed, with the TEF higher for protein, than for carbohydrates and fat.
Top 10 richest protein and lowest kilocalorie food/100g 43 Kcal/11 g egg white 57 Kcal/11 g octopus 68 Kcal/13 g squid, /14 g ray 71 Kcal/14 g shrimp, /17 g cod 72 Kcal/14g cuttlefish, /11 g palourde 78 Kcal/16 g John dory, /16 g ombrine 80 Kcal/16 g dogfish, /19 g pike 83 Kcal/17 sole 84 Kcal/12 mussel 86 Kcal/15 trout
Diabetesmellitus: epidemyology Diabetesmellitusisoccuringat epidemicrates in the US and in mostpartsof the world. The number of adults with diabetes in the world is projected to increase from 135 million in 1995 to 300 million in 2025. In the US approximately 15 million have diabetes and approximately 15 million have impaired fasting glucose levels. Of special concern is the emergence of type 2 diabetes in adolescents, closely linked to the fourfold increase in prevalence of obesity in children and teens in the past 30 years. Diabetes is the fifth leading cause of death in the US and cost annually 132 billion dollars.
Diabetesmellitus: classification Metabolicderangements in the metabolism of glucose and profoundabnormalities in the metabolism of fat, protein, and othersubstancescharacterize the pathologyof diabetes. A heterogeneous disorder both genetically and clinically, all classifications of diabetes have in common hyperglycemia, attributable to either insulin insufficiency or insulin resistance. Insulin-dependent diabetes mellitus (type 1) Non-insulin-dependent diabetes mellitus (type 2)
Etiologicclassificationofdiabetes Diabetes Type 1 diabetes (beta-cell destruction with lack of insulin) Type 2 diabetes (insulin resistance with relative insulin deficiency) Other specific types: genetic defects of beta-cell function; genetic defects of insulin action; diseases of the exocrine pancreas; endocrinopathies (acromegaly); drug or chemical-induced; infectious; Gestational diabetes mellitus
Diabetesmellitus: classification Type 1 diabetesaccountsforapproximately 5% ofdiabetes and ismanifestedbyinsulindeficiencycausedbydestructionof the pancreaticbeta-cells. Type 2 diabetes accounts for about 90% of diabetes and iscaracterized by twoprimarydefects: insulinresistence (diminishedtissuesensitivity to insulin) and impaired beta cellfunction (delayed or inadequateinsulin release. Othercauses account for the remaining 5% ofdiabetes in the UnitedStates
Criteriafordiagnosisofdiabetes Symptoms of diabetes plus casual plasma glucose values of ≥ 200 mg/dL. Casual is defined as any time of day without regard to time since last meal. Classic symptoms of diabetes include polydipsia, polyuria and unexplained weight loss. Fasting plasma glucose value ≥ 126 mg/dL. Fasting is defined as no energy intake for at least 8 hours. 2-hour postload plasma glucose value of ≥ 200 mg/dL during an oral glucose tolerance test.
Diabetesmellitus: roleofhormones Glucosehomeostasisisorchestratedbyanexquisite interplay ofpancreatic and guthormones. The mostimportant are insulin and glucagon. Insulinis the hormoneprimarilyresponsiblefor the metabolism and storageof the body fuelsthat are ingested. The pancreas sustains a basal level of insulin release and secrets additional insulin in response to increased blood glucose after a meal. The postprandial secretion of insulin promotes glucose, amino acids, and fat uptake bi tissues (primarily liver, adipose and muscle tissue) where the glucose is used or stored.
Diabetesmellitus: roleofhormones Insulin production decreasesasthe blood glucose level decreases. Glucagon, is secreted by the pancreatic αcells in responsetodecreasedbloodglucoselevels and under conditionsof stress. Glucagonstimulatesglucosereleasefromliver. The balancebetweeninsulin and glucagonlevelsisvitalfornormalglucosehomeostasis, fatty acid metabolism, and proteinpreservation.