OBESITY A GLOBAL EPIDEMIC

0
Number of obese people in the world in 2030
Homme qui mange un hamburger

Obesity and overweight

Obesity is a complex disease involving an excessive amount of body fat. Obesity is not just a cosmetic problem. It is a medical problem that increases the risk of other diseases and health problems, such as heart disease, diabetes, high blood pressure and certain cancers.

 There are many reasons why some people find it difficult to avoid obesity. In general, obesity results from a combination of hereditary factors, environmental factors and personal choices about diet and exercise.

 The good news is that even modest weight loss can improve or prevent the health problems associated with obesity. Dietary changes, increased physical activity and behavioural changes can help you lose weight. Prescription drugs and weight loss procedures are additional options for treating obesity.

Obesity affects quality of life

Obesity can lower your overall quality of life. You may not be able to do the things you used to do, such as participating in enjoyable activities. You may avoid public places. People with obesity may even face discrimination.

Other weight-related problems can affect your quality of life:

  • Depression
  • Disability
  • Sexual problems
  • Shame and guilt
  • Social isolation
  • Decreased professional success

Body Mass Index

Body Mass Index (BMI) is a person’s weight in kilograms divided by the square of height in meters. A high BMI can be an indicator of high body fatness. BMI can be used to screen for weight categories that may lead to health problems but it is not diagnostic of the body fatness or health of an individual.

icon01-free-img

IMC below 18,5

Underweight

icon02-free-img

IMC from 18,5 to 25

Normal (healthy weight)

icon03-free-img

IMC from 25 to 30

Overweight

icon01-free-img

IMC from 30 to 35

Obese Class I (Moderately obese)

icon02-free-img

IMC from 35 to 40

Obese Class II (Severely obese)

icon03-free-img

IMC over 40

Obese Class III (Very severely obese)

Diagnosing obesity

BMI is an approximate calculation of a person’s weight in relation to their height. There are other more accurate measures of body fat and its distribution:

  • Skinfold thickness tests
  • Waist to hip comparisons
  • Screening tests, such as ultrasound, CT and MRI scans.

Your doctor may also order certain tests to help diagnose the health risks associated with obesity. These may include:

  • Blood tests to look at cholesterol and glucose levels
  • Liver function tests
  • Diabetes screening
  • Thyroid tests
  • Heart tests, such as an electrocardiogram (ECG or EKG).

A measurement of the fat around your waist is also a good indicator of your risk of obesity-related diseases.

Femme obèse

The causes of obesity

Although there are genetic, behavioural, metabolic and hormonal influences on body weight, obesity occurs when you take in more calories than you expend through exercise and normal daily activities. Your body stores these excess calories as fat.

Most Americans’ diets are too high in calories, often from fast food and high-calorie drinks. People who are obese may eat more calories before they feel full, feel hungry sooner, or eat more because of stress or anxiety.

RISK FACTORS

Obesity is usually the result of a combination of causes and contributing factors:

Family heritage and influences

The genes you inherit from your parents can influence the amount of body fat you store and how that fat is distributed. Genetics may also play a role in how efficiently your body converts food into energy, how it regulates your appetite and how it burns calories during exercise.

Obesity tends to be hereditary. This is not just because of the genes they share. Family members also tend to have similar eating and activity patterns.

Lifestyle choices

Unhealthy diet. A high-calorie diet, low in fruit and vegetables, high in fast food, high-calorie drinks and oversized portions contributes to weight gain.

Liquid calories. You can drink a lot of calories without feeling full, especially calories from alcohol. Other high-calorie beverages, such as sweetened soft drinks, can contribute to significant weight gain.

Inactivity. If you have a sedentary lifestyle, you can easily take in more calories each day than you burn through exercise and your usual daily activities. Looking at computer, tablet and phone screens is a sedentary activity. The number of hours you spend in front of a screen is strongly associated with weight gain.

Certain diseases and medications

In some people, obesity can be attributed to a medical cause, such as Prader-Willi syndrome, Cushing’s syndrome and other conditions. Medical conditions, such as arthritis, can also lead to decreased activity, which can result in weight gain.

Some medications can cause weight gain if you don’t compensate with diet or activity. These include some antidepressants, anticonvulsants, diabetes drugs, antipsychotics, steroids and beta blockers.

Social and economic factors

Social and economic factors are linked to obesity. It is difficult to avoid obesity if you do not have safe areas to walk or exercise. Similarly, you may not have been taught how to cook healthily or have access to healthier foods. Also, the people you spend time with can influence your weight – you are more likely to develop obesity if you have obese friends or relatives.

Age

Obesity can occur at any age, even in young children. But with age, hormonal changes and a less active lifestyle increase the risk of obesity. In addition, the amount of muscle in your body tends to decrease with age. In general, the decrease in muscle mass leads to a lower metabolism. These changes also reduce caloric needs and can make it more difficult to maintain excess weight. If you don’t consciously control what you eat and become more physically active as you age, you may gain weight.

Other factors
  • Pregnancy. Weight gain is common during pregnancy. Some women find this weight difficult to lose after the birth of the baby. This weight gain can contribute to the development of obesity in women. Breastfeeding may be the best way to lose the weight gained during pregnancy.
  • Smoking cessation. Quitting smoking is often associated with weight gain. And for some, this can lead to enough weight gain to qualify as obesity. This often happens because people use food to cope with smoking cessation. In the long run, however, quitting smoking is always more beneficial to your health than continuing to smoke. Your doctor can help you prevent weight gain after you stop smoking.
  • Lack of sleep. Not getting enough sleep or sleeping too much can cause hormonal changes that increase your appetite. You may also crave high-calorie, high-carbohydrate foods, which can contribute to weight gain.
  • Stress. Many external factors that affect your mood and well-being can contribute to obesity. People often seek out higher calorie foods when they are experiencing stressful situations.
  • The microbiome. Your gut bacteria are affected by what you eat and can contribute to weight gain or difficulty losing weight.
  • Previous attempts to lose weight. Previous attempts to lose weight followed by rapid weight regain can contribute to further weight gain. This phenomenon, sometimes called yo-yo dieting, can slow down your metabolism.
  • Even if you have one or more of these risk factors, it does not mean that you are destined to develop obesity. You can counteract most risk factors through diet, physical activity and exercise, and behavioural changes.
Complications

People with obesity are more likely to develop a number of potentially serious health problems, including:

  • Heart disease and stroke. Obesity makes you more likely to have high blood pressure and abnormal cholesterol levels, which are risk factors for heart disease and stroke.
  • Type 2 diabetes. Obesity can affect the way your body uses insulin to control blood sugar. This increases the risk of insulin resistance and diabetes.
  • Certain cancers. Obesity can increase your risk of cancer of the uterus, cervix, endometrium, ovary, breast, colon, rectum, oesophagus, liver, gallbladder, pancreas, kidney and prostate.
  • Digestive problems. Obesity increases the likelihood of developing heartburn, gallbladder disease and liver problems.
  • Gynaecological and sexual problems. Obesity can cause infertility and irregular periods in women. Obesity can also cause erectile dysfunction in men.
  • Sleep apnea. Obese people are more likely to suffer from sleep apnoea, a potentially serious condition in which breathing stops and starts repeatedly during sleep.
  • Osteoarthritis. Obesity increases pressure on weight-bearing joints and promotes inflammation in the body. These factors can lead to complications such as osteoarthritis.
  • Serious symptoms of COVID-19. Obesity increases the risk of developing severe symptoms if you are infected with the virus that causes coronavirus 2019 (COVID-19). People with severe cases of COVID-19 may need treatment in intensive care units or even mechanical assistance to breathe. 

Top 10 ways to measure your body fat

Skinfold measurements have been used to assess body fat for over 50 years. Skinfold sizers measure the thickness of your subcutaneous fat – the fat under the skin – at certain points on the body. Measurements are taken at 3 or 7 different locations on the body. The specific sites used vary for men and women.

For women, the triceps, the area above the hip bone and the thigh or abdomen are used for the 3-site measurement. For a 7-site measurement in women, the chest, the area near the armpit and the area under the shoulder blade are also measured.

For men, the three sites are the chest, abdomen and thigh, or the chest, triceps and area below the shoulder blade. For a 7-site measurement in men, the areas near the armpit and below the scapula are also measured.

  • Advantages: Skinfold sizers are very affordable and measurements can be taken quickly. They can be used at home and are also portable.
  • Disadvantages: The method requires practice and basic knowledge of anatomy. Also, some people do not like having their fat pinched.
  • Availability: Calipers are affordable and easy to buy online.
  • Accuracy: The skill of the person performing the skinfolds can vary, which has an impact on accuracy. Measurement errors can range from 3.5 to 5% of body fat.

IN CONCLUSION

Estimating body fat percentage using skinfold measurement is affordable and relatively simple once you know how to do it. However, the accuracy depends on the skill of the person performing the assessment.

Body shape varies from person to person, and the shape of your body provides information about your body fat. Measuring the circumference of certain body parts is a simple method of body fat estimation. For example, the US Army uses a body fat calculation that simply requires an individual’s age, height and a few circumference measurements. For men, the circumferences of the neck and waist are used in this equation. For women, the circumference of the hips is also included.

  • Advantages: This method is easy and affordable. A flexible measuring tape and calculator are all you need. These tools can be used at home and are portable.
  • Disadvantages: Body circumference equations may not be accurate for all people due to differences in body shape and fat distribution.
  • Availability: A flexible measuring tape is easily available and very affordable.
  • Accuracy: The accuracy can vary widely based on your similarity to the people used to develop the equations. The error rate can be as low as 2.5–4.5% body fat, but it can also be much higher.

IN CONCLUSION

Using body circumference to estimate body fat is quick and easy. However, the accuracy of this method can vary considerably and is not considered an ideal method for measuring body fat percentage.

As the name implies, DXA uses X-rays of two different energies to estimate your body fat percentage. During a DXA scan, you lie on your back for approximately 10 minutes while an X-ray scans over you. The amount of radiation from a DXA scan is very low. It’s about the same amount you receive during three hours of your normal life. DXA is also used to assess bone density and provides detailed information about the bone, lean mass and fat in separate body regions (arms, legs and torso).

  • Advantages: This method provides accurate and detailed information, including a breakdown of different body regions and bone density readings.
  • Disadvantages: DXAs are often unavailable to the general public, expensive when available and deliver a very small amount of radiation.
  • Availability: A DXA is typically only available in medical or research settings.
  • Accuracy: A DXA provides more consistent results than some other methods. The error rate ranges from 2.5–3.5% body fat.

IN CONCLUSION

DXA is more accurate than many other methods of assessing body fat percentage. However, it is often not available to the general population, is quite expensive and is not feasible for regular testing.

This method, also known as underwater weighing or hydrodensitometry, estimates your body composition based on its density. This technique weighs you while submerged under water after exhaling as much air as possible from your lungs. You are also weighed while you are on dry land, and the amount of air left in your lungs after you exhale is estimated or measured. All of this information is entered into equations to determine the density of your body. Your body’s density is then used to predict your body fat percentage.

  • Advantages: It’s accurate and relatively quick.
  • Disadvantages: It’s difficult or impossible for some individuals to be fully submerged under water. The method requires breathing out as much air as possible, then holding your breath underwater.
  • Availability: Hydrostatic weighing is typically only available at universities, medical settings or certain fitness facilities.
  • Accuracy: When testing is performed perfectly, the error of this device can be as low as 2% body fat.

IN CONCLUSION

Hydrostatic weighing is an accurate way to assess your body fat. However, it’s only available at certain facilities and involves holding your breath while being completely submerged in water.

Similar to hydrostatic weighing, air displacement plethysmography (ADP) estimates your body fat percentage based on the density of your body. However, ADP uses air instead of water. The relationship between the volume and pressure of air allows this device to predict the density of your body. You sit inside an egg-shaped chamber for several minutes while the pressure of the air inside the chamber is altered. To obtain accurate measurements, you need to wear skin-tight clothing or a bathing suit during testing.

  • Advantages: The method is accurate and relatively quick, and it does not require being submerged in water.
  • Disadvantages: ADP has limited availability and can be expensive.
  • Availability: ADP is typically only available at universities, medical settings or certain fitness facilities.
  • Accuracy: The accuracy is very good, with an error rate of 2–4% body fat.

IN CONCLUSION

The Bod Pod is the main ADP device currently used. It predicts your body fat with air rather than water. It has good accuracy, but it’s typically only available at certain medical, research or fitness facilities.

BIA devices detect how your body responds to small electrical currents. This is done by placing electrodes on your skin. Some electrodes send currents into your body, while others receive the signal after it has passed through your body tissues. Electrical currents move through muscle easier than fat due to the higher water content of muscle. The BIA device automatically enters your body’s response to the electrical currents into an equation that predicts your body composition. There are many different BIA devices that vary widely in cost, complexity and accuracy.

  • Advantages: BIA is quick and easy, and many devices can be purchased by consumers.
  • Disadvantages: The accuracy varies widely and can be greatly affected by food and fluid intake.
  • Availability: While many units are available to consumers, these are often less accurate than the expensive devices used in medical or research settings.
  • Accuracy: Accuracy varies, with an error rate that ranges from 3.8–5% body fat but may be higher or lower depending on the device used.

IN CONCLUSION

BIA devices work by sending small electrical currents through your body to see how easily they travel through your tissues. Many different devices are available, although advanced devices produce more accurate results.

BIS is similar to BIA in that both methods measure the body’s response to small electrical currents. BIS and BIA devices look similar but use different technology. BIS uses a much larger number of electrical currents than BIA, in addition to high and low frequencies, to mathematically predict your amount of body fluid. BIS also analyzes the information differently, and some researchers believe that BIS is more accurate than BIA. However, similar to BIA, BIS uses the body fluid information it gathers to predict your body composition based on equations. The accuracy of both of these methods depends on how similar you are to the people for whom these equations were developed.

  • Advantages: BIS is quick and easy.
  • Disadvantages: Unlike BIA, consumer-grade BIS devices are not currently available.
  • Availability: BIS is typically only available at universities, medical settings or certain fitness facilities.
  • Accuracy: BIS is more accurate than consumer-grade BIA devices but has a similar error rate to more advanced BIA models (3–5% fat).

IN CONCLUSION

Similar to BIA, BIS measures your body’s response to small electrical currents. However, BIS uses more electrical currents and processes the information differently. It’s fairly accurate but mostly used in medical and research settings.

Electrical impedance myography is a third method that measures your body’s response to small electrical currents. However, while BIA and BIS send currents through your whole body, EIM sends currents through smaller regions of your body. Recently, this technology has been used in inexpensive devices that are available to consumers. These devices are placed on different parts of the body to estimate the body fat of those specific areas. Because this device is placed directly on specific body regions, it has some similarities to skinfold calipers, although the technologies are very different.

  • Advantages: EIM is relatively quick and easy.
  • Disadvantages: Very little information is available about the accuracy of these devices.
  • Availability: Cheap devices are available to the general public.
  • Accuracy: Limited information is available, although one study reported 2.5–3% error relative to DXA.

IN CONCLUSION

EIM injects electrical currents into small body regions. Portable devices are placed directly on different body parts to estimate the body fat percentage at those locations. More research is needed to establish the accuracy of this method.

3D body scanners use infrared sensors to get a detailed look at the shape of your body. The sensors generate a 3-D model of your body. For some devices, you stand on a rotating platform for several minutes while the sensors detect your body shape. Other devices use sensors that rotate around your body. The scanner’s equations then estimate your body fat percentage based on your body shape. In this way, 3-D body scanners are similar to circumference measurements. However, a greater amount of information is provided by a 3-D scanner.

  • Advantages: A 3-D body scan is relatively quick and easy.
  • Disadvantages: 3-D body scanners are not commonly available but gaining popularity.
  • Availability: Several consumer-grade devices are available, but they’re not as affordable as simple circumference-measurement methods like skinfold calipers.
  • Accuracy: Limited information is available, but some 3-D scanners may be fairly accurate with errors of around 4% body fat.

IN CONCLUSION

3-D scanners are a relatively new method of assessing body fat percentage. The method uses information about your body shape to predict your body fat percentage. More information is needed about the accuracy of these methods.

Multi-compartment models are considered to be the most accurate method of body composition assessment. These models split the body into three or more parts. The most common assessments are called 3-compartment and 4-compartment models. These models require multiple tests to get estimates of body mass, body volume, body water and bone content. This information is obtained from some of the methods already discussed in this article. For example, hydrostatic weighing or ADP can provide body volume, BIS or BIA can provide body water and DXA can measure bone content. Information from each of these methods is combined to build a more complete picture of the body and obtain the most accurate body fat percentage.

  • Advantages: This is the most accurate method available.
  • Disadvantages: It’s often unavailable to the general public and requires multiple different assessments. It’s more complex than most other methods.
  • Availability: Multi-compartment modeling is typically only available in select medical and research facilities.
  • Accuracy: This is the best method in terms of accuracy. Error rates can be under 1% body fat. These models are the true “gold standard” that other methods should be compared to.

IN CONCLUSION

Multi-compartment models are very accurate and considered the “gold standard” for body fat assessment. However, they involve multiple tests and are not typically available to the general public.

0