By William Cabot, M.D., FAAOS.
THE GROWING PROBLEM OF OBESITY
The past half-decade in the United States and elsewhere has seen what can only be described as an astronomical increase in the numbers of obese people in our general population. It is also true that these same obese people parent children who are at increased risk for obesity (1). The behavioral patterns of eating the wrong foods and lack of exercise are learned early in life by actions and interactions between parent and child and have long-lasting biologic and behavioral consequences.
We do have what can be termed an “obesity epidemic”. Although there are many in the population that eat correctly and exercise, there still remains a considerable segment afflicted with morbid obesity and the negative consequences associated with that condition.
Statistics show that approximately 65% of the population routinely sits instead of stands, drives instead of walks, and rides the elevator instead of taking the stairs, which puts those Americans at an increased risk for chronic diseases such as hypertension, coronary artery disease, and diabetes (2).
Diabetes is a condition which results in a higher than normal level of blood glucose. That level is controlled by a hormone produced in our body called insulin.
Insulin is a peptide (protein) hormone made by the pancreas that regulates our blood glucose levels. The part of the pancreas responsible for the production of insulin is known as “The islets of Langerhans”.
Insulin has many functions (3):
- Insulin enables glucose, which results from metabolism of consumed carbohydrates, to leave the blood stream and enter the cells of the body where it is used for energy production.
- Insulin utilizes excess glucose by enabling the liver and muscle to store it as a substance called glycogen which can be used later for energy production.
- Insulin also reduces blood glucose by reducing glucose production in the liver.
- Insulin plays a part in the production of protein (4).
TYPE I AND TYPE II DIABETES
Diabetes is a condition in which a person’s blood glucose levels are higher than they are supposed to be.
Type 1 diabetes is a condition that typically develops in childhood and is characterized by little or no production of insulin, and subsequently high blood glucose levels. It is the result of a poorly functioning pancreas.
Type 2 diabetes, also known as adult onset diabetes, typically develops in middle aged or older adults (but can also appear in teenage years) and is also characterized by high blood glucose levels. It is the result of the body’s inability to use insulin effectively to lower blood glucose. There is a direct relationship between morbid obesity and Type 2 diabetes (3). There is also statistical confirmation that the prevalence of Type 2 diabetes is on the rise (5). At least part of this is due to the obesity epidemic described above.
THE IMPORTANCE OF EXERCISE
It is now well documented that regular physical exercise is a significant determinant in whether you develop Type 2 diabetes and if you do how easy or difficult it may be to control your blood sugar levels (11). Regular exercise cannot only help control blood glucose levels but it also has the ability to prevent or delay the development of Type 2 diabetes.. Exercise alone enables glucose to cross the cell membrane more easily where it can be utilized for energy.
MEASURING BLOOD GLUCOSE
The normal blood sugar levels for people who do not have diabetes are (6):
- Fasting blood glucose 100 mg/dl or less
- Less than 140 mg/dL at 2 hours after meals.
Two types of tests enable your doctor to calculate your blood sugar level
- A1C test- This tests how high your blood sugar was during the previous three months. A score of 6.5 percent or less is optimal.
- Blood glucose level test. The normal values are given above.
Insulin resistance is a condition in which the body’s cells do not respond as they should to the production of insulin. Insulin is produced, however muscle, fat, and liver cells don’t respond normally and the appropriate amount of glucose is not absorbed from the bloodstream. This results in an elevated glucose level in the blood (3, 7).
To compensate for this situation the cells in the pancreas increase production of insulin in an attempt to decrease the glucose level. Over time individuals with this disorder frequently develop Type 2 diabetes because the pancreas cannot produce enough insulin to keep glucose levels low enough.
THE RELATIONSHIP BETWEEN OBESITY AND INSULIN RESISTANCE
Many experts believe that obesity, especially excess fat around the waist, is a significant contributing cause of insulin resistance (3, 8). In the past many scientists felt that fatty tissue was simply a storage depot for energy to be used when necessary.
We now are aware of the fact that belly fat produces harmful substances that can create a condition of chronic inflammation in the body. This is extremely harmful and can result in a multitude of health issues including arthritis, heart disease and many other maladies (9).
Prediabetes is a condition in which a person’s blood glucose or A1C levels are higher than normal but not high enough for a diagnosis of diabetes. Obesity, is a potential cause of individuals transitioning from prediabetes to Type 2 diabetes. Physical inactivity and sleep apnea are also known to be contributing factors (3).
BMI-THE BODY MASS INDEX-A MEASURE OF OBESITY
Body mass index (BMI) is a measure of body fat based on height and weight that applies to adult men and women (10). A score over 30 is considered obesity.
Bariatric weight loss surgery is typically considered for individuals with a BMI over 35 or 40 who have not been successful in losing weight by more conventional methods such as diet and exercise or at 35 for those who have already developed medical problems as a result of their obesity.
We are definitely making progress in our ability to diagnose and treat diabetes and obesity, a significant cause of many medical maladies. Moving forward one cannot escape the conclusion that the more sedentary lifestyle and poorer eating habits that are prevalent today created many of the medical issues described and merit top priority in our efforts to achieve a healthier life.
- Gortmaker SL et al; Am J Dis Child. 1987 May;141(5):535-40. Increasing Pediatric Obesity in The United States.
- Agatson A.; Circulation. 2012 Jul 3; 126(1)e3-5, Cardiology Patient Page. Why America is fatter and sicker than ever:
- Wilcox G et al; Insulin and insulin resistance: Clin Biochem Rev 2005 May;26(2):19-39.
- Proud CG; Regulation of protein synthesis by insulin: Biochem Soc Trans. 2006 Apr;34(Pt 2):213-6
- Shaw JE et al; Global estimates of the prevalence of diabetes for 2010 and 2030: Diabetes Res Clin Pract.. 2010 Jan;87(1):4-14.
- Lebovitz HE; Insulin resistance:definition and consequences; Exp Clin Endocrinol Diabetes. 2001;109 Suppl 2:S135-48.
- Kahn B. et al; Obesity and insulin resistance: J Clin Invest:2000 Aug 15;106(4):473-481.
- Colberg SR et al;Exercise and type 2 diabetes:Diabetes Care.2010 Dec;33(12):e147-e167.