Scientific Inquiry Tied to Genetics, Evolution, and Obesity

Scientific Inquiry The field of nutrition is based on scientific study that integrates : Biology Physiology Microbiology Botany Chemistry Genetics and Molecular biology In order to understand how evidence is produced, it is crucial to understand the basics of scientific inquiry.

The Scientific Method Is hypothesis driven Follows a basic format – Ask a question (define the problem) – Form a hypothesis – Design an experiment – Collect, analyze & interpret the data – Generalize & publish the findings – Ask another question (the findings generally leads to more questions)

The Scientific Method

Examples of Theories in Science and Nutrition Cell The cell is the most basic unit of life, organisms are made of one or more cells, and new cells arise from existing cells. Years ago it was hypothesized that humans are born with a certain number of fat cells. Now it is known that fat cells can divide when they have been filled to capacity. Set Point There seems to be a range of body weight that is relatively easy to maintain and is genetically and physiologically controlled. The lower body weight range is more tightly defended to prevent starvation and preserve life. There are many feedback mechanisms that influence intake and satiety.

Research Designs Case studies Clinical studies Intervention trials Epidemiology Laboratory experiments Testimonials are NOT Testimonials are NOT based on research based on research

Study Types Case: Results from a single person protocol conducted by a medical doctor. Clinical: Experimental design with a group of people. Epidemiological & Intervention: Population based, retrospective or prospective. Laboratory: Experimental design with any life form; microorganisms, virus, animals, plants, cell lines, bugs, etc.

Experimental Design things to consider 1. Number of Subjects: is there enough for statistical significance. 2. Duration of the Study: is it long enough for conclusions to be made. 3. Matching Groups: Ethnicity, gender, age, lifestyle, disease. 4. Control Groups: experimental vs placebo. 5. Reproducible Results: can the experiment be repeated and yield the same results. 6. The Treatment Protocol: blind, double blind, crossover.

Treatment Protocol Blind: the subject does not know if they are in the experimental or control group. Double Blind: the subject and the primary investigator do not know who is in the experimental or control group. Cross over: each group experiences a period of being on the placebo and experimental drug. A highly reputable study design is called the double-blind cross over experiment.

Public Recommendations Consistent results from multiple credible studies published over many years are used to make dietary recommendations. A whole body of evidence, collected over many years of experimentation is interpreted by the scientific community to create public recommendations regarding diet and health (disease prevention).

OBESITY Obesity is body fatness significantly in excess of the level that is consistent with optimal health. Excess body fat is stored inside fat cells (adipose tissues) That causes the mass or size of the fat cells increases. It known as Hypertrophy. Once fat cells are filled up, then the fat cells can be divided or increase in cell number. This is referred to as Hyperplasia. There has been an uncontrolled rise in obesity in the United States over the last 20 years.

Obesity Trends* Among U.S. Adults BRFSS, 1991, 1999, 2008, and

Obesity Obesity was 12% in 1991 and 33.8% in 2010 More than 17% of children and adolescents age 2 to 19 years of age are obese. The obesity during the last 20 years has doubled in adults and tripled in children. Obesity is defined by Body Mass Index (BMI).

OBESITY AS A CHRONIC DISEASE Too much body increases a person's risk of developing a host of chronic health problems, those include: High Blood pressure Heart Disease Diabetes Gallbladder Disease Arthritis Sleep Disorder (sleep apnea) Respiratory Problems Cancers of Breast, Uterus, Prostate, and Colon

BMI Body Mass Index

Body Mass Index (BMI) It is current standard for assessing healthfulness of body weight. Which determined by dividing weight (in kg) by height (in meters) square: BMI=wt. (Kg)/height (m) or BMI=wt. (lbs.)/height (In)2x705 BMI=140 lbs/(66)2in.=140/4356=0.0321x705 BMI=22.65 or 23

BMI The Healthy BMI for adults is between: 18.5 to 24.9 People with in this range have lowest health risks. BMI is not actually a measure of body fat It is recommended as a way to assess body fatness

BMI 18.5 or less underweight 18.5 – 24.9 normal over weight obese type I obese type II 40.0 or higher extremely obese

Module 4.2

Principles of Energy Balance 1 pound fat = 3500 Calories stored. To lose body fat, a Calorie deficit needs to be created. To gain body weight, a Calorie excess needs to be created. Body weight changes are based on the relationship of Caloric (Energy) intake & Energy Expenditure.

Energy Balance Equations Body Fat Mass change can be calculated with these formulas: If Calories Consumed = Calories Expended (Isocaloric ) Body weight is typically maintained. Energy balance occurs. If Calories Consumed > Calories Expended (positive energy balance) Weight is typically gained. Positive energy balance occurs. If Calories Consumed < Calories Expended (negative energy balance) Weight is typically lost. Negative energy balance occurs.

Energy Intake Consumption of Energy Producing Nutrients in Food and Beverages Protein (4 Calories per gram) Carbohydrate (4 Calories per gram) Fat (9 Calories per gram) Alcohol (7 Calories per gram) All of the Calories add up!

Energy Expenditure Basal Metabolic Rate (BMR: 60%– 65%) An amount of energy needed to sustain life Voluntary muscle movement-(Physical Activity: 25%-35%) Calories burned in physical activity (PA) The specific dynamic action (SDA) of food (also called the thermic effect of food: 5%-10%) Energy required for food digestion & processing

Energy Expenditure

Basal Metabolic Rate (BMR): The energy required by the body to minimally function (heart to beat, lungs to breathe, …). It is determined in a fasting state (12 hours) and when the body is at complete rest. Majority of expenditure in a sedentary person

Basal Metabolic Rate (BMR): BMR is also called Resting Energy Expenditure (REE) It considers the amount of energy burned by a person at rest. REE can be measured in the lab or estimated using the Mifflin Equations.

The Mifflin Equations Are based on gender, height, weight, and age REE Formula For WOMEN: REE (Calories/day) = (10 x W) + (6.25 x H) – (5 x A) REE Formula For MEN: REE (Calories/day) = (10 x W) + (6.25 x H) – (5 x A) + 5 W= Weight in Kg (pounds divided by 2.2) H = Height in centimeters (inches x 2.54) A= Age in years

Factors That Affect The BMR - Age - Gender - Growth - Body Composition - Fever - Stress - Environmental Temperature - Fasting/ Starvation - Malnutrition - Thyroxin

Physical Activity (PA): The energy expended to perform physical activity. The total amount of energy expended increases with body weight and the intensity of the exercise. The BMR or REE can be used to determine energy spent or Calorie burn in Physical Activity.

Physical Activity & Calorie Burn Calories burned = Hours spent in activity x REE x Activity Factor ÷ 24 hours/day. Activity factors Sleeping/Reclining: Factor of 1 Very Light Activity: sitting or standing in a small space: Factor of 1.5 Light Activity: moving without sweating: Factor of 2.5 Moderate Activity: moving and sweating: Factor of 5.0 Strenuous Activity: all out efforts that cannot be sustained for more than a few minutes without exhaustion: Factor of 7.0

Specific Dynamic Action (SDA): The food processing charge. Also called the thermic effect of food. ~10% of the total number of Calories consumed is required for the digestion, absorption & assimilation of nutrients into the body. Metabolism is increased when fed

Module 4.3

NEW YEAR RESULATION

HEALTHY BODY WEIGHT “This year I am going to loose my weight once and for all” Three (3) misconceptions Focus on weight The focus on controlling wt. Focus on a short term plan

HEALTHY BODY WEIGHT It is not your weight you need to control It is fat in proportion to lean(The Body Composition) Controlling body composition is not possible- without controlling your behavior. Sporadic bursts of activity (dietary) are not effective It is a life time commitment

Body Composition Determination of body weight should be based upon body composition. It is important to know the % of total body weight that is fat. Values should be considered for maintaining good health, personal appearance, & performance reasons

Essential Fat Mass Two classifications of body fat – Essential – necessary for optimal health Fat in bone marrow Cell membranes – Nonessential or storage Subcutaneous adipose tissue. Visceral Fat

Body Weight vs. Body Fat

The best way to determine obesity is to determine the % of body fat.   is too fat if ≥20% body fat.   is too fat if ≥26% body fat

Interpreting Body Fat

Determining Body Fat Underwater weighing (very accurate) Bod Pod (very accurate)-Air Displacement Technique Skin fold calipers (the more sights, the better) Bioelectrical impedance (the persons hydration level affects the reading accuracy) Futrex 5000 (more accurate when average body fat)-Light absorption, reflectance,& near-infrared spectroscopy. Research Techniques (DEXA, MRI, total body potassium, substance dilution)

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Location of Body Fat

Location of fat in body affects the risks associated with having too much fat. Excess Subcutaneous Fat increase health risks relatively less than the excess Visceral Fat. Visceral fat is more metabolically active than subcutaneous fat.

Location of Body Fat Based on the fat deposit in the body prople are dividied into two groups: “Apple” profile “Pear” profile Central Obesity Fat that collects deep within the central abdominal area of the body (visceral fat)

RICKS FROM CENTRAL OBESITY Visceral Fat. Especially dangerous with regard to risks of: Diabetes Stroke Hypertension Dyslipidemia High Blood Cholesterol Coronary artery disease

Factors affecting fat distribution Smoking Moderate-to-high intake of alcohol Physical activity Menopause in women

Waist Measurement Reflects the degree of visceral fatness in proportion to body fatness. Men 40 inches(102 cm) Women 35 inches(88 cm) Anyone with the waist measurement larger than these standards may carry an increased risk of disease.

Combating Obesity

Diets: Low carb &/or very low Calorie There is 6% success rate for reducing weight and maintaining the weight loss by dieting. During prolonged fasting (or low calorie, low carb diets), the BMR declines and lean body mass is used to make glucose for brain, central nervous system, and red blood cell functioning. The body chemistry changes under conditions of Feasting & Fasting

Feasting

Short Fasting

Long Fasting

Weight Control When considering weight loss, it is important to lose the excess fat weight and preserve the lean body mass or muscle. The reason for weight loss should be to decrease excess of body fat. Fat weight loss is a slow process.

Effective Weight Loss Optimal weight loss rate is 1 lb/week. 1 lb of fat weight loss requires a 3500 Calorie deficit A 500 Calorie deficit per day times 7 days per week produces a rate of weight loss of 1 lb/week.

500 Calorie Deficit/Day 40 minutes aerobic exercise = 300 Calories (preserves LBM, BMR and utilizes stored fat) 22g of dietary fat removed from the diet = 200 Calories. Results in: 1 pound per week of body fat lost. Preservation of lean body mass. A faster rate of weight loss forces the body to use muscle protein to meet the glucose/energy needs of the body.

Combating Obesity Surgery: Lipo-suction Intestinal resection Gastric bypass Gastric band Drugs: Over the counter & prescribed These methods can be health threatening & usually do not result in long-term sustained weight loss and/or a healthy lifestyle

Role of Exercise in Weight Control Exercise is critical in the maintenance of a healthy body weight. Furthermore, it improves: Cardiovascular fitness Raise HDL Slow Heart rate Decrease blood pressure Support brain health Maintain lean body mass Make bones stronger Increase flexibility, strength and endurance

Role of Exercise in Weight Control Spot reduction, or reducing fat mass in one part of the body, is a weight-loss myth. Fat does not belong to the muscles Fat in fat cells increase or decrease uniformly

Weight Control Weight control is easier if a person develops: Long term Consistent healthy Lifestyle behaviors

Behavior Modification Identify goal (realistic). Identify current behaviors that need to change. Identify behaviors that will achieve the goal & reinforce them. Commit to change. Plan (set realistic small behavior changes into action, rewards). Persist long enough to see results, reinforces motivation. Evaluate the progress & modify the plan

Life Long Diet Protocols Greater long term success rates with: 1. Eating a well balanced diet from a variety of foods to achieve nutrient adequacy. 2. Incorporating an hour-long exercise program daily. 3. Using behavior modification to permanently incorporate desired health behaviors

Optimal Dietary Planning for Adequacy Optimal Dietary Planning involves ensuring that the diet meets standards for promoting health and nutrient adequacy To do so, one must limit: Saturated Fatty Acids Trans Fatty acids Cholesterol Added sugars and Salt Make sure the %age of Calories from Carbohydrate, Fat and protein are with AMDR range.

What is Nutritional Adequacy? The diet provides: Essential nutrients Fiber Energy to maintain health. Nutritional adequacy should be considered for each individual diet. In weight loss, weight maintenance or gain diets, nutritional adequacy should also be considered.

How Nutritional Adequacy is Measured? Dietary assessment tools like: Diet Analysis software programs Food Composition tables & databases The Exchange System Used to prescribe & monitor dietary intake.

All diets (especially weight control diets) need to be planned so that there are no nutritional inadequacies, deficiencies, or risks for toxicity. Inadequate Intake: < 100% of the DRI Deficient Intake: < 66% of the DRI Risk of Toxicity: > 100% of the UL