OBESITY: Diagnosis and Treatment

                        Diagnosis and Treatment of OBESITY 

Obesity is a complex disease involving an excessive amount of body fat obesity isn't just a cosmetic concern it's a medical problem. That increases the risk of other diseases as well.  Obesity can be estimated by calculating the body mass index. BMI is a ratio of the weight of the body expressed in kgs divided by height of the individual in meter square so this ratio is indicative of your body mass so if this ratio is lesser than 25 it is considered normal. If it is greater than 25 and it is in between 30 then you are slightly overweight. If this ratio is more than 30 then you are obese. Obesity is life-threatening because it is associated with several other diseases such as heart attack stroke type 2 diabetes cancers etc. 

In simple words, obesity is the silent killer. According to the Centers for Disease Control CDC, 40 percent of the population in the USA has a high chance of developing obesity which is a big concern. We need calories for our functioning and the calories come from the food we take such as carbohydrate-protein or fat that gives us the energy, we need to keep ourselves going. but the problem occurs when we eat more and spend less in simple words, we exercise less so in that situation body stores the excess energy in other forms.  It also matters what kind of food we eat. Whether we are eating healthy food versus unhealthy food. When we eat more calories and we are able to burn fewer calories then we are in a state of calorific excess. The body can deal with these excess calories in three possible ways.  

First of all, it can convert the excess fuel to fat and store it in adipose tissue. 

The second body can burn the fuel by doing exercise.  

Third and lastly there could be wastage of this excess fuel via the production of heat.  

Now our body is evolutionarily trained to store excess calories in terms of fat. Because in the early days there was not so much of availability of food so whenever the body has some amount of calorie which is excess it would store it for the future. That worked like a survival strategy in the past but nowadays, we have plenty of food so we never go to a state where we are devoid of food or devoid of calories. Excess calories along with a sedentary lifestyle created a huge problem and this is the result. We are getting obese.  

In our population, the fraction of obese people is increasing day by day. Dealing with obesity requires proper knowledge and we need to understand what are the checks and balances that our body applies to control the body weight. Because many of these mechanisms are compromised in obese individuals so there is a Lipostat hypothesis or we can say Lipostat Theory.  

LIPOSTAT Theory: It turns out our body can estimate how much fat. We have and it tries to keep the fat in a balanced state known as the set point. Now when our fat level increase or decrease our body can sense that by a plethora of sensors. These sensors can interact with several molecular players and ultimately it can bring down the fat or bring up the fat into a set point level and this homeostatic mechanism is crucial for weight management. Obviously, we can understand in obese individuals one possible aspect is the defect of these Lipostat mechanisms. One such sensor is leptin which is a hormone secreted by adipose tissues itself.  

This hormone carries a message that fat reserves are sufficient so at this particular point fuel intake should be decreased and expenditure of energy should be increased. Now when the mass of the adipose tissue increases leptin secretion also increases. Increased leptin secretion inhibits feeding and fat synthesis. Also, it stimulates the oxidation of fatty acids. When the mass of the adipose tissue decreases insulin secretion and also the leptin secretion decreases. This results in greater food intake and less fatty acid oxidation. Now you must be wondering that you are eating a lot but your friend which is very lean he eats a lot, but never get fat why is.  

Obesity is not directly proportional to the calorific input. It turns out there are complex genetic neuronal and the hormonal mechanism that regulates our feeding and fasting behavior. Leptin modulates our hunger circuit. In simple words, we have two different categories of neurons in our hunger circuit, an Anorexigenic neuron and an Orexigenic neuron. Anorexigenic neurons promote eating whereas and orexigenic neurons inhibit eating. Leptin positively stimulates the anorexigenic neuron or eats fewer neurons and negatively stimulates eat more neurons. As a consequence, our hunger feeling is suppressed when leptin is more and we end up spending more and more calories. Now this leptin or the leptin receptor is encoded by genes so any mutation in the leptin gene or the gene that produces the leptin receptor could be the underlying cause of obesity as well. 

This is a list of genes that are associated with obesity as per CDC.   

Gene Symbol	Gene name	Gene products role in energy balance
ADPIOQ	Adipocytes, and collagen domain containing	Produced by fat cells, adiponectin promotes energy expenditure.
FTO	Fat mass and obesity-associated gene	Promote food intake.
LEP	Leptin	Produced by fat cells.
LEPR	Leptin receptor	When bound by leptin, inhibits appetite
INSIG2	Insulin-induced gene2	Regulation of cholesterol and fatty acids synthesis
MC4R	Melanocortin 4 receptor	When bound by alpha melanocytes stimulating hormone, stimulates appetite.
PCSK1	proprotein convertase subtilisin/Kexin type 1	Regulates insulin biosynthesis
PPARG	peroxisome proliferator-activated receptor gamma	Stimulate lipid uptake and development of fat tissue.

Now we understand the underlying causes of obesity, there could be several reasons. 

One of that could be genetic as well and recent research has shown beyond genetics. Epigenetic mechanisms are also involved in obesity. All these genetic and epigenetic mechanisms are not in our control, but we can modify our lifestyle. We can restrict our calorific input. we can increase our exercise to manage our body weight nowadays intermittent fasting is a really popular practice to reduce body weight and keep a check on it. Intermittent fasting can help in weight loss and weight management in obese individuals in intermittent fasting.  

You fast for 16 hours approx, and you have a feeding schedule of 8 hours. This ensures the body can utilize all the fat during this fasting period and it can break down the fat to make energy. Other than intermittent fasting dietary modifications such as the keto diet low carb diet could be useful for weight loss. We learned that obesity is a common disease. It's kind of like a lifestyle disease that is affecting every age group in our population. Obesity can be genetic and sporadic as well we also looked at the underlying mechanisms that can trigger obesity.