What is obesity?
Obesity is a complex disorder related to lifestyle, environment and genes. It is a condition where there is excessive fat storage in the body which increases the risk of health problems. The World Health Organisation (WHO) has declared obesity as the largest global chronic problem, including in India. Almost 30-65% of Indians are either overweight or obese, directly correlating with the increasing prevalence of obesity-related comorbidities: hypertension, metabolic syndrome, dyslipidemia, type 2 diabetes, cardiovascular disease, stroke, osteoarthritis, sleep apnoea, respiratory problems, certain cancers, polycsytic ovary syndrome (PCOS), infertility and gestational diabetes in women.
A proper body weight is most conducive to good health. Increase or decrease from this normal body weight beyond certain limits are not only detrimental to health but also predispose a person to many other disorders. There should be a balance between energy intake and expenditure.
What happens when there is an imbalance in energy intake and expenditure?
Several neural, hormonal and chemical mechanisms help maintain the body weight by keeping a balance between energy intake and energy expenditure. If there is more energy consumed than expended, then the remaining energy is stored in the body in form of either glycogen or fat (depending upon the periods), such an imbalance is called a positive imbalance. You consume more energy and expend less, the excess energy then gets stored in the body. Now, if you consume less energy and expend more, such an imbalance is called negative energy imbalance.
Both of these imbalances show symptoms over a period of time. If there is a chronic positive imbalance, then you might start seeing fat deposits and gain in your weight over a period of time. Therefore, it is very important to create a balance between energy intake and expenditure.
Let’s try to understand what are the risk factors of chronic obesity?
Genetic inheritance influences a person’s chances of becoming obese. Many hormonal and neural factors involved in weight regulation are determined by genetic factors. The number and size of fat cells, regional distribution of body fat and resting metabolic rate are also influenced by genes. Nutritional or lifestyle choices can activate or deactivate these obesity-triggering genes. Various genes are involved in weight regulation, but these following caught much attention, the Ob gene, adiponectin (ADIPOQ) gene, the “fat mass and obesity related gene”, FTO gene and the beta 3-adrenoreceptor gene. It is also seen that the FTO gene predisposes the individuals to diabetes by its effect on body mass.
Lack of exercise and a sedentary lifestyle, accompanied by chronic overeating are also one of the most pressing causes of chronic obesity. The increase in screen-time and decrease in exercise routine is increasing sedentary lifestyle.
Sleep and stress
Shortened sleep alters the endocrine regulation of hunger and appetite. Hormones that affect appetite take over and may promote excessive energy intake. Thus recurrent sleep deprivation can modify the amount, composition, and distribution of food intake and may contribute to the obesity epidemic.
Stress is another factor. The cortisol hormone is released when an individual is under stress, and stimulates insulin release to maintain blood glucose levels in the “fight-or-flight” response. Thus an increase in appetite occurs. Chronic stress with constantly elevated cortisol levels can also lead to appetite changes. Cortisol levels are typically high in the early morning and low around midnight.
Taste, satiety and portion sizes
Just imagine that you are in a buffet and there are numerous delicious options of food in front of you. What will you do? Will you try to resist or will you just put the amount of food on your plate for which you are actually hungry? Or would you rather like to try each and every option available and increase the amount of food?
Well, food gives us satisfaction, we all crave for something or other. When provided with numerous options, an individual ends up eating more, totally ignoring his/her hunger. We think that just adding half a piece of cake or a muffin will not do too much! But all these extra calories add up.
Therefore, there is a direct correlation between taste and portion sizes. Once you keep on eating extra portions, you’ll form a habit and then going back to eating according to your hunger feels difficult.
Gut microflora and diet
You must be wondering what can be the relationship between gut microbes and the diet you consume? Well, researchers have identified a complex relationship between the both, i.e., microflora gut population and food absorption. There are two microbes present in the gut- firmicutes and bacteroidetes. These two live in a symbiotic relationship, one acting as slimming and the other acts as fattening microbe. Firmicutes bacteria tend to be much more efficient at nutrient breakdown and calorie absorption than bacteroidetes, and therefore contribute to calorie absorption and the development and maintenance of chronic obesity in individuals. A higher number of bacteroidetes, on the other hand, may help to make or keep people lean. Weight loss, then, it appears would require a higher number of bacteroidetes and a lower number of firmicutes. (Reference: Krause’s food and nutrition care process, 14th ed).
Now let’s briefly understand how you diagnose chronic obesity?
Body weight and height are measures of body size and based on these, BMI (body mass index) is the most researched measure of generalised obesity. It helps in assessing the nutritional status, identifying individuals at risk, and monitoring the efficacy of a nutrition intervention. It also provides information about the body’s stores of fat and muscle.
In anthropometric measurements, one can measure weight, height, waist circumference (for abdominal obesity), and waist to hip ratio (WHR).
Classification of obesity based on Body Mass Index (BMI) (kg/m2):
Waist circumference cut offs for Asian Indians:
|Action level 1
|Action level 2
|Should avoid gaining weight
|Seek medical help
Assessment of physical activity:
Physical activity tells a lot about the lifestyle of an individual. It is very important to assess how active a person is. It can be measured by questionnaire, direct observation and using electronic monitoring devices such as pedometers (to measure step counts) and heart rate monitors.
It is crucial to know the diet of a person. What is she/he eating and how much. Food choices and food portions make a huge difference and therefore should be assessed properly. Generally a 24 hour dietary recall is done by a nutritionist to understand all about diet. It can be done through a questionnaire or by asking one to one or by asking the person to maintain a food diary.
After discussing what obesity is, what are the risk factors and how can you assess is a person is obese or not, now is the time to understand why is chronic obesity harmful? You must know that obesity is a reversible disorder. With proper diet, exercise and lifestyle modification, you can bring your weight down in the normal ranges. Of Course there are a few factors such as genetics which are not in your control. But such factors can be easily managed by taking care of modifiable factors, such as diet, physical activity, sleep and stress.
Why reaching a higher BMI can be dangerous to your health?
Chronic obesity leads to psychological problems, mechanical disabilities, predisposition to renal, metabolic and cardiovascular diseases and overall reduces life expectancy.
Obesity is a disorder which is metabolically unhealthy. It can predispose you to many complications. Chronic heart disease, diabetes, hypertension, gall-bladder disorder, stroke, cataract, PCOS, sleep apnea, hormonal cancers, gout and osteoarthritis are just a few complications which tend to worsen if you are obese.
Being obese always doesn’t mean that you can get these complications. There are people who are obese and still living a healthy life. But the risk of development of such complications is always a concerning factor.
If we talk in terms of BMI, then many studies suggest that a normal BMI increases longevity but any deviation from the normal range, i.e, 18-22.9 kg/m2 can reduce the longevity and quality of life.
Furthermore, if you look at the consequences of obesity, you’ll see how much chronic obesity really costs.
The extra weight load of the body may cause flat feet and arthritis leading to pain in hips, knees and spine. Moreover, adipose tissue deposition in the chest region and under the diaphragm interferes with normal respiration and predisposes to bronchitis. This further makes breathing difficult and the person feels sleepy and drowsy throughout the day.
What is the relationship between obstructive sleep apnea and obesity?
Obstructive sleep apnea (OSA) is characterized by episodes of complete collapse of the airway or partial collapse leading to deprivation of breathing and oxygen temporarily. OSA is linearly related to obesity because in chronic obesity fat gets deposited in the chest area making the airways narrow. The muscle activity in this region also decreases and there are frequent episodes of hypoxia (having low oxygen level in tissues). Furthermore, such episodes can alter heart rate, drop in oxygen saturation and loud breathing sounds. It impacts cardiovascular health as well.
Obesity is one of the major risk factors for OSA which further leads to other comorbidities such as hypertension, CAD, depression, insulin resistant diabetes and sleep related accidents.
Obesity is one of the major leading risk factors for non-alcoholic fatty liver disease which can further develop end-stage liver disease. Fat deposits on the liver causes various other problems and further causes alterations in metabolism of macronutrients.
Obesity is also related to increased risk of gallbladder disease. Moreover, the production of cholesterol and the amount of serum cholesterol is reported to correlate with body weight and the number of fat cells.
Obesity and heart disease:
With the increased fatty deposits in the body, there is an increased risk of atherosclerosis, stroke and heart attack. The fatty built-up in the arteries make them narrow leading to atherosclerosis. Furthermore, it becomes difficult for blood to pass through the narrow arteries leading to hypoxia and cell death. This makes the heart work more and more to pump blood with more efficacy. Moreover, myocardial infarction, congestive heart failure are few conditions which can develop over time if the heart keeps on working in such stressful conditions.
Understand more about heart disease by reading How to prevent heart disease? A step by step detailed guide for you.
Do you know the relationship between obesity and type 2 diabetes mellitus?
Obesity can worsen diabetes and it is also one the major risk factors of developing diabetes. In obesity there is hyperinsulinemia and insulin resistance or impaired insulin uptake by receptors in target tissues. Insulin resistance is common in obesity and can be reversed. Furthermore, the fat deposition in abdomen and central obesity is one of the major reasons for insulin resistance. Moreover, in these conditions the cells resist the insulin present in the body leading to elevated blood glucose levels. Chronically such conditions develop into pre-diabetes and then to diabetes.
To understand more about pre-diabetes and insulin resistance, give a read to Understanding Pre-diabetes and insulin resistance!
PCOS and obesity
Due to hormonal disbalance, obesity is one of the risk factors for PCOS. in fact, menarche is found to occur generally at a younger age in overweight or obese girls. Irregular menstrual cycle and increased menstrual abnormalities are also experienced by females.
To know how to manage PCOS, give a read to A comprehensive guide- PCOS and Dietary Habits
Obesity leads to psychological problems such as anxiety, stress and depression. Furthermore, fatigue, drowsiness and irregular sleep cycles cause such psychological conditions. An obese person may also suffer from personality complexes and may disassociate him/her self from the society.
Obesity associates with many comorbidities such as coronary artery disease, diabetes, hypertension, stroke, obstructive sleep apnea, PCOS, psychological conditions, etc. Above all, obesity can reduce life expectancy and may also tarnish quality of life. Obesity is a reversible condition and therefore, one should work towards reversing it for a sustainable life. Moreover, with a proper diet, physical activity and lifestyle and behavioral modification, one can easily win over obesity and lead a happy and healthy life!
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