Obesity; Types, Causes, Symptoms, Diagnosis, Treatment

Obesity is a medical condition in which excess body fat has accumulated to the extent that it may have a negative effect on health. People are generally considered obese when their body mass index (BMI), a measurement obtained by dividing a person’s weight by the square of the person’s height, is over 30 kg/m², with the range 25–30 kg/m² defined as overweight. Some East Asian countries use lower values. Obesity increases the likelihood of various diseases and conditions, particularly cardiovascular diseases, type 2 diabetes, obstructive sleep apnea, certain types of cancer, osteoarthritis and depression.

Calculation of obesity

Body Mass Index (BMI) is a mathematical calculation involving height and weight, irrespective of family history, gender, age or race. BMI is calculated by dividing a person’s body weight in kilograms by their height in meters squared (weight [kg] height [m]2) or by using the conversion with pounds (lbs) and inches (in) squared as shown below, This number can be  misleading, however, for very muscular people, or for pregnant or lactating women.

[Weight (lbs) ÷ height (in)2  ] x 704.5 =BMI

BMI calculator

The BMI cutoffs are

Health Canada classifies BMI according to the associated risk of developing health problems

BMI value	Classification*	Health risk
Less than 18.5	Underweight	Increased
18.5 to 24.9	Normal weight	Least
25.0 to 29.9	Overweight	Increased
30.0 to 34.9	Obese class I	High
35.0 to 39.9	Obese class II	Very high
40 or higher	Obese class III	Extremely high

Causes of Obesity

There are many causes that directly and indirectly contribute to obesity. Behavior, environment and genetics are among the main contributors to obesity. The Centers for Disease Control has identified these three as the main causes to the complexity of the obesity epidemic.

Behavior

In today’s fast-paced environment, it is easy to adopt unhealthy behaviors. Behavior, in the case of obesity, relates to food choices, amount of physical activity you get and the effort to maintain your health.

Americans are consuming more calories on average than in past decades. The increase in calories has also decreased the nutrients consumed that are needed for a healthy diet. This behavioral problem also relates to the increase in portion sizes at home and when dining out.

Environment

Environment plays a key role in shaping an individual’s habits and lifestyle. There are many environmental influences that can impact your health decisions. Today’s society has developed a more sedentary lifestyle. Walking has been replaced by driving cars, physical activity has been replaced by technology and nutrition has been overcome by convenience foods.

Genetics

Science shows that genetics play a role in obesity. Genes can cause certain disorders which result in obesity. However, not all individuals who are predisposed to obesity become affected by obesity. Research is currently underway to determine which genes contribute most to obesity.

Gut bacteria

The study of the effect of infectious agents on metabolism is still in its early stages. Gut flora has been shown to differ between lean and obese humans. There is an indication that gut flora in obese and lean individuals can affect the metabolic potential. This apparent alteration of the metabolic potential is believed to confer a greater capacity to harvest energy contributing to obesity.

Sedentary lifestyle

A sedentary lifestyle plays a significant role in obesity.Worldwide there has been a large shift towards less physically demanding work,and currently at least 30% of the world’s population gets insufficient exercise.This is primarily due to increasing use of mechanized transportation and a greater prevalence of labor-saving technology in the home.In children, there appear to be declines in levels of physical activity due to less walking and physical education.

Other illnesses

Certain physical and mental illnesses and the pharmaceutical substances used to treat them can increase risk of obesity. Medical illnesses that increase obesity risk include several rare genetic syndromes (listed above) as well as some congenital or acquired conditions: hypothyroidism, Cushing’s syndrome, growth hormone deficiency,^[129] and the eating disorders: binge eating disorder and night eating syndrome.

Physiological influences

Some researchers believe that every person has a predetermined weight that the body resists moving away from. Also, people of the same age, sex and body size often have different metabolic rates. This means their bodies burn food differently. Someone with a low metabolic rate may require fewer calories to maintain approximately the same weight as someone whose metabolic rate is high.

• Medical problems. In some people, obesity can be traced to a medical cause, such as Prader-Willi syndrome, Cushing’s syndrome and other conditions. Medical problems, such as arthritis, also can lead to decreased activity, which may result in weight gain.
• Certain medications – Some medications can lead to weight gain if you don’t compensate through diet or activity. These medications include some antidepressants, anti-seizure medications, diabetes medications, antipsychotic medications, steroids and beta blockers.
• Social and economic issues –  Research has linked social and economic factors to obesity. Avoiding obesity is difficult if you don’t have safe areas to exercise. Similarly, you may not have been taught healthy ways of cooking, or you may not have money to buy healthier foods. In addition, the people you spend time with may influence your weight — you’re more likely to become obese if you have obese friends or relatives.
• Age  – Obesity can occur at any age, even in young children. But as you age, hormonal changes and a less active lifestyle increase your risk of obesity. In addition, the amount of muscle in your body tends to decrease with age. This lower muscle mass leads to a decrease in metabolism. These changes also reduce calorie needs, and can make it harder to keep off excess weight. If you don’t consciously control what you eat and become more physically active as you age, you’ll likely gain weight.
• Pregnancy – During pregnancy, a woman’s weight necessarily increases. Some women find this weight difficult to lose after the baby is born. This weight gain may contribute to the development of obesity in women.
• Quitting smoking – Quitting smoking is often associated with weight gain. And for some, it can lead to enough weight gain that the person becomes obese. In the long run, however, quitting smoking is still a greater benefit to your health than continuing to smoke.
• Lack of sleep – Not getting enough sleep or getting too much sleep can cause changes in hormones that increase your appetite. You may also crave foods high in calories and carbohydrates, which can contribute to weight gain.

Others Cause of Obesity 

• Eating large amounts of processed or fast food– that’s high in fat and sugar
• Drinking too much alcohol– alcohol contains a lot of calories, and people who drink heavily are often overweight
• Eating out a lot – you may be tempted to also have a starter or dessert in a restaurant, and the food can be higher in fat and sugar
• Eating larger portions than you need – you may be encouraged to eat too much if your friends or relatives are also eating large portions
• drinking too many sugary drinks– including soft drinks and fruit juice
• comfort eating– if you have low self-esteem or feel depressed, you may eat to make yourself feel better
• an increased intake of energy-dense foods that are high in fat; and
• an increase in physical inactivity due to the increasingly sedentary nature of many forms of work, changing modes of transportation, and increasing urbanization.

Obesity caused others health problem

Obesity can cause a number of further problems, including difficulties with daily activities and serious health conditions.

• High blood pressure
• High cholesterol
• breathlessness
• increased sweating
• snoring
• difficulty doing physical activity
• often feeling very tired
• joint and back pain
• low confidence and self-esteem
• feeling isolated

Being obese can also increase your risk of developing many potentially serious health conditions, including:

• type 2 diabetes – a condition that causes a person’s blood sugar level to become too high
• high blood pressure
• high cholesterol and atherosclerosis (where fatty deposits narrow your arteries), which can lead to coronary heart diseaseand stroke
• asthma
• metabolic syndrome – a combination of diabetes, high blood pressure and obesity
• several types of cancer, including bowel cancer, breast cancerand womb cancer
• gastro-oesophageal reflux disease (GORD) – where stomach acid leaks out of the stomach and into the oesophagus (gullet)
• gallstones – small stones, usually made of cholesterol, that form in the gallbladder
• reduced fertility
• osteoarthritis – a condition involving pain and stiffness in your joints
• sleep apnoea – a condition that causes interrupted breathing during sleep, which can lead to daytime sleepiness with an increased risk of road traffic accidents, as well as a greater risk of diabetes, high blood pressure and heart disease
• liver disease and kidney disease
• pregnancy complications, such as gestational diabetes or pre-eclampsia (when a woman experiences a potentially dangerous rise in blood pressure during pregnancy)

Symptoms of Obesity 

The primary warning sign of obesity is an above-average body weight.

• breathing disorders (e.g., sleep apnea, chronic obstructive pulmonary disease)
• certain types of cancers (e.g., prostate and bowel cancer in men, breast and uterine cancer in women)
• coronary artery (heart) disease
• depression
• diabetes
• gallbladder or liver disease
• gastroesophageal reflux disease (GERD)
• high blood pressure
• high cholesterol
• Trouble sleeping
• Sleep apnea. This is a condition in which breathing is irregular and periodically stops during sleep.
• Shortness of breath
• Varicose veins
• Skin problems caused by moisture that accumulates in the folds of your skin
• Gallstones
• Osteoarthritis in weight-bearing joints, especially the knees
• High levels of blood sugar (diabetes)
• High triglycerides levels

Diagnosis of Obesity 

These exams and tests generally include

• Taking your health history – Your doctor may review your weight history, weight-loss efforts, exercise habits, eating patterns, what other conditions you’ve had, medications, stress levels and other issues about your health. Your doctor may also review your family’s health history to see if you may be predisposed to certain conditions.
• A general physical exam – This includes also measuring your height; checking vital signs, such as heart rate, blood pressure and temperature; listening to your heart and lungs; and examining your abdomen.
• Calculating your BMI – Your doctor will check your body mass index (BMI) to determine your level of obesity. This should be done at least once a year. Your BMI also helps determine your overall health risk and what treatment may be appropriate.
• Measuring your waist circumference – Fat stored around your waist, sometimes called visceral fat or abdominal fat, may further increase your risk of diseases, such as diabetes and heart disease. Women with a waist measurement (circumference) of more than 35 inches (80 centimeters, or cm) and men with a waist measurement of more than 40 inches (102 cm) may have more health risks than do people with smaller waist measurements.
• Checking for other health problems – If you have known health problems, your doctor will evaluate them. Your doctor will also check for other possible health problems, such as high blood pressure and diabetes.
• Blood tests – What tests you have depend on your health, risk factors and any current symptoms you may be having. Tests may include a cholesterol test, liver function tests, a fasting glucose, a thyroid test and others. Your doctor may also recommend certain heart tests, such as an electrocardiogram.

Treatment of Obesity 

Weight reduction is achieved by

• Consuming fewer calories
• Increasing activity and exercise

Structured approaches and therapies to reduce weight include:

• A modified diet. A reasonable weight loss goal is 1 to 2 pounds per week. This can usually be achieved by eating 500 to 1,000 fewer calories each day. Whether you concentrate on eating less fat or fewer carbohydrates is up to you. Fats have more than twice as many calories per ounce than carbohydrates or protein. If you cut out carbohydrates, you still need to limit fat intake. Choose healthy fats, such as monounsaturated and polyunsaturated oils.
• Regular exercise – To effectively lose weight, most people need to do moderate intensity exercise for 60 minutes most days of the week. Add more activity during the day. Take the stairs and get up often from your desk or sofa.
• Non-prescription orlistat (Alli) – Orlistat inhibits fat absorption in the intestine. Until recently, this medication was only available by prescription (Xenical). The over-the-counter medicine is sold at a lower dose than Xenical. But the active ingredient is the same.
• Other non-prescription diet pills –  Over-the-counter diet pills often contain ingredients that can increase heart rate and blood pressure. It is not clear how effective they are in producing weight loss that can be maintained over time. Common side effects include feeling jittery and nervous and having heart palpitations. Some experts believe they may be associated with an increased risk of stroke.
• Prescription diet pills. To help you lose weight, your doctor may prescribe medications along with a calorie-restricted diet. Almost all people regain weight when they stop using these medications. The effects of long-term use of these drugs have not been determined.
• Exercise. People who are overweight or obese need to get at least 150 minutes a week of moderate-intensity physical activity to prevent further weight gain or to maintain the loss of a modest amount of weight. To achieve more-significant weight loss, you may need to exercise 300 minutes or more a week. You probably will need to gradually increase the amount you exercise as your endurance and fitness improve.
• Keep moving – Even though regular aerobic exercise is the most efficient way to burn calories and shed excess weight, any extra movement helps burn calories. Making simple changes throughout your day can add up to big benefits. Park farther from store entrances, rev up your household chores, garden, get up and move around periodically, and wear a pedometer to track how many steps you actually take over the course of a day.

Dietary changes to treat obesity include

• Cutting calories – The key to weight loss is reducing how many calories you take in. You and your health care providers can review your typical eating and drinking habits to see how many calories you normally consume and where you can cut back. You and your doctor can decide how many calories you need to take in each day to lose weight, but a typical amount is 1,200 to 1,500 calories for women and 1,500 to 1,800 for men.
• Feeling full on less – The concept of energy density can help you satisfy your hunger with fewer calories. All foods have a certain number of calories within a given amount (volume). Some foods — such as desserts, candies, fats and processed foods — are high in energy density. This means that a small volume of that food has a large number of calories. In contrast, other foods, such as fruits and vegetables, have lower energy density.
• Making healthier choices – To make your overall diet healthier, eat more plant-based foods, such as fruits, vegetables and whole-grain carbohydrates. Also emphasize lean sources of protein — such as beans, lentils and soy — and lean meats. If you like fish, try to include fish twice a week.
• Restricting certain foods  – Certain diets limit the amount of a particular food group, such as high-carbohydrate or full-fat foods. Ask your doctor which diet plans have been found effective and which might be helpful for you.
• Meal replacements –These plans suggest that you replace one or two meals with their products — such as low-calorie shakes or meal bars — and eat healthy snacks and a healthy, balanced third meal that’s low in fat and calories.

Surgery of Obesity 

In general, weight-loss surgery (called bariatric surgery) may be considered if your BMI is 40 or greater, or your BMI is 30-35 or greater and you have at least one medical condition directly related to obesity. In addition, you must have participated in a structured weight loss program without success.

Common weight-loss surgeries include

• Gastric bypass surgery – In gastric bypass (Roux-en-Y gastric bypass), the surgeon creates a small pouch at the top of your stomach. The small intestine is then cut a short distance below the main stomach and connected to the new pouch. Food and liquid flow directly from the pouch into this part of the intestine, bypassing most of your stomach.
• Laparoscopic adjustable gastric banding (LAGB) – In this procedure, your stomach is separated into two pouches with an inflatable band. Pulling the band tight, like a belt, the surgeon creates a tiny channel between the two pouches. The band keeps the opening from expanding and is generally designed to stay in place permanently.
• Biliopancreatic diversion with duodenal switch – This procedure begins with the surgeon removing a large part of the stomach. The surgeon leaves the valve that releases food to the small intestine and the first part of the small intestine (duodenum). Then the surgeon closes off the middle section of the intestine and attaches the last part directly to the duodenum. The separated section of the intestine is reattached to the end of the intestine to allow bile and digestive juices to flow into this part of the intestine.
• Gastric sleeve – In this procedure, part of the stomach is removed, creating a smaller reservoir for food. It’s a less complicated surgery than gastric bypass or biliopancreatic diversion with duodenal switch.
• Gastroplasty – also known as stomach stapling. A surgeon creates a small pouch in the stomach that allows only limited amounts of food to be eaten at one time.
• Laparoscopic adjustable gastric banding – A surgeon places an adjustable band around the stomach with minimally invasive surgery.

Complications of Obesity 

Other complications from obesity or becoming overweight are:

1. Neurological – headaches, stroke, dementia , vision loss from diabetes complications, false brain tumors, and diabetic neuropathy

2. Psychological – depression, anxiety, unnecessary stress, and eating disorders

3. Respiratory – asthma, sleep apnea, pulmonary embolism, and pulmonary hypertension

4. Urological – may lead to kidney cancer and diabetic kidney disease.

5. Circulatory – high blood pressure, high cholesterol, irregular heartbeat, atherosclerosis, poor circulation, heart problems, blood clots, peripheral artery disease, and certain lymph node cancers

6. Muskuloskeletal – arthritis (hips, knees, and ankles), lower back pain, and vertebral disk disease.

7. Gastrointestinal – acid reflux disease, esophageal cancer, colon cancer, colon polyps, fatty liver disease, cirrhosis, gallstones, liver cancer, and gallbladder cancer.

8. Digestive – pancreatitis, pancreatic cancer, and type 2 diabetes.

9. Reproductive – for women irregular menstruation, infertility, ovarian cancer, endometrial cancer, cervical cancer, breast cancer, and polycystic ovarian syndrome. For men: erectile dysfunction, infertility, and prostate cancer.