Obesity is a popular cause for concern, as it has doubled since 1980.

 

Obesity affects children too; in 2012, 40 million children under the age of 5 were overweight.

 

In 2008, 35% of the world’s population over the age of 20 was overweight. That means that 1.4 billion adults were overweight in 2008. Currently obesity kills more people than malnourishment. 

 

Obesity

 

Obesity’s main causes reside in bad diets and sedentary lifestyles. However, it may be the result of an underlying condition. The cause and treatment are determined when you visit a doctor.

 

Your Body Mass Index (BMI) is used to indicate whether you have a healthy weight.

It is calculated by dividing your weight and your height squared. You can use the following calculator to assess your weight.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The following is a chart that places you in a weight category.

 

 

 

 

 

 

 

 

 

 

 

 

Source: Adpated from "Chapter 78, Figure 78-2." Harrison's Principles of Internal Medicine. New York, N.Y.: McGraw-Hill, 2012.

 

Why do we gain weight?

 

Evolution made human beings capable of storing energy inside the body in two ways, by fat (adipose tissue) and by glycogen in muscles and the liver. When humans were nomads and didn’t have nearby food sources the storage of energy was crucial for survival.

 

Nowadays, locating food is simple; we can go to the supermarkets, fast food restaurants etc. Therefore, storing energy is now a problem. Nomads also walked and exercised every day keeping a balance in the ingestion and use of energy. Today, our lifestyle is more sedentary and with new modes of transportation systems, walking to our destination is no longer a habit.

 

To maintain a healthy weight, we must spend the same amount of energy we ingest. Our bodies have sensors that regulate and acknowledge how much energy we store as fat.

There are four components that regulate weight: leptin, produced by the adipose tissue, insulin, produced by the pancreas, ghrelin, produced by the stomach and peptide YY, produced by the intestines.

 

Leptin reduces hunger and the use of energy stored.

 

Insulin is explained in the section of DM II.

 

Ghrelin produces hunger.

 

Peptide YY maintains satiety.

 

There are two systems that are involved in weight loss and weight gain, catabolism and anabolism respectively. Anabolism is in charge of increasing the ingestion of food and inhibiting the expenditure of energy. Catabolism inhibits the ingestion of food and promotes the use of fat as fuel.

 

Leptin is secreted when the body has too much fat in storage, therefore it helps regulate weight.

 

The ability of storing energy as fat is important for two reasons. First, the weight of fat is lighter than that of glycogen. Glycogen is another way the body stores energy and it is composed of multiple glucose molecule chains. The space for glycogen storage is limited and if we were able to store the same amount of fat in the form of glycogen, we would weigh 110 pounds more!

 

The second reason is the following: by burning fat we obtain way more energy (calories) than by using carbohydrates and proteins. This means we can live up to 30-40 without eating and with enough water, due to this energy storage system.

 

Complications

 

Obesity is the cause of many difficulties and numerous life threatening diseases.

 

1. Cardiovascular (see Hypertension)

   1. Hypertension

   2. Congestive heart disease

   3. Coronary artery disease

2. Respiratorias

   1. Dyspnea (difficulty breathing)

3. Gastrointestinal

   1. Acid reflux

   2. Gallstones

   3. Colon cancer

4. Endocrine

   1. Diabetes Mellitus Tipo II (see Diabetes)

   2. Dyslipidemia (see Dyslipidemia)

5. Musculoskeletal

   1. Osteoarthritis (joint pain)

   2. Back pain

   3. Immobility

6. Genitourinary

   1. Breast and uterus cancer

   2. Complications during pregnancy

7. Psychological

   1. Depression 

8. Neurological

   1. Brain hemorrhages

   2. Dementia

 

Prevention

 

In order to prevent obesity you need to have a healthy diet and exercise daily. It is also important to visit your doctor to rule out Hypothyroidism, Polycystic ovary, Cushing’s syndrome or a medication that causes weight gain.

 

 

Bibliography:

1. Harrison's Principles of Internal Medicine. New York, N.Y.: McGraw-Hill, 2012. Capítulo 78.

2. Kumar, Vinay, and Stanley L. Robbins. Robbins Basic Pathology. Philadelphia, PA: Saunders/Elsevier, 2007. Pág. 303-319.

3. WHO. Noncommunicable Diseases (NDC) Country Profiles. 2014.