Fat chemistry: the science behind obesity

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Tuesday, May 8, 2018
fat chemistry: the science behind obesity

As a bariatric surgeon and a weight loss expert I always wonder why some people put on weight so easily. A lot of patients actually put in effort and lose weight but as soon as they stop the program, the weight tends to come back and sometimes they regain even more than what they had lost in the first place. So, what is it that makes people suffer from obesity in the first place?

1.    Genetic causes: We cannot blame our genes entirely but they do play a major role in the development of obesity. Heritability estimates of up to 40 to 70% show that there is a significant genetic susceptibility component in the development of obesity [1]. Based on suspected genetic etiology, obesity can be classified into (a) Monogenic obesity (b) Syndromic obesity and (c) polygenic or common obesity. 

While monogenic obesity is a result of 20 single gene disruptions mainly to do with leptin, syndromic obesity arises from discreet genetic defects or chromosomal abnormalities and leads to specific syndromes such as “Prader Willi syndrome or Bardt Beidl syndrome”. Monogenic and syndromic obesity have been widely studied by researchers, but patients suffering from such genetic issues form a very small percentage of the actual obese population. 

It is the polygenic or common obesity that affects most people who suffer from obesity. Although research on this front is ongoing and many genes have been implicated, a lot of them point towards the central nervous system. These genes appear to be involved with the regulation of appetite, satiety, energy expenditure, feeding behaviour, motivation and decision making. This could partly explain why some people are fabulous at controlling their cravings and some give in so easily. Its not about “will-power”, it is probably about your genetic make-up [2, 3]. 

2.    Environmental causes: There is no doubt that obesity is highly heritable but an obesogenic environment is necessary for its manifestation. Obesogenic environment is mainly constituted by two factors (a) nutrition (b) physical activity.

Obesogenic environment may sometimes even start in the pre-natal period. Early life influences like the mother’s weight gain and high blood sugar levels along with a history of smoking during pregnancy may lead to increased levels of obesity in these children. Babies with low birth weight have also shown to have a higher predisposition to obesity in adult life. It is also said that babies who are breastfed have lesser chances of becoming obese.

Talking about nutrition, in his path breaking book, “The Dorito Effect”, Mark Schatzker takes us through the journey of the food industry over the last 70 years. Food manufactures have consistently focused on pest resistance and appearance of food, not its flavour. When our grandmothers said that chicken of today does not taste the same or the tomatoes are not sour enough, they were indicating towards a paradigm shift in the way our food is produced. “Fake” is the flavour of the day. As the so called natural food continues to plummet in taste and nutritional value, the economic graphs of the artificial flavour industry have seen an unprecedented growth. 

Not only are we witnessing a steep degradation in the nutritional value of natural foods, we are also subjected to an over-abundance of junk and processed food that is so easily available and at much cheaper rates. Our environment is almost one hundred percent obesogenic!

Human beings are lazy creatures. It is no wonder that no other species thought about inventing the “wheel”. Machines have made our lives easy but they have also made us more sedentary. Today technology has surpassed our imagination, but there is always a price to pay. 

3.    The set point theory: There are many scientists who believe in the set point theory of weight regulation. According to this theory, internal regulatory controls create a set point for a body’s weight. Some people tend to have a higher setting than others and thus have a higher body weight. The theory states that your body will work hard to maintain a given weight that is pre-set. So, how much ever effort one puts in to diet and exercise to lose weight, ultimately the body will fight to bounce back to its setpoint. Most people suffering from obesity will identify with this phenomenon. However, there are a few detractors of this theory as well who would argue that this theory may give just another excuse to the patients to not put in efforts into diet and exercise.

4.    Stress and sleep: I think that this deserves a special mention. As doctors and patients, all of us tend to undermine the importance of stress and sleep in our lives. Stress is a common thread that ties all the loose ends in the chain that leads to obesity. Similarly lack of sufficient sleep has been linked to weight gain. Stress and sleep are deeply connected with emotional and physical well-being and hence it is vital to pay attention to these two aspects when we are dealing with weight gain and obesity.

There are various other causes such as hormonal issues and drugs etc which we shall discuss in the next article. 

What I have mentioned above is just a gist of the commonly known causes of obesity. Obesity is one of the most serious diseases being faced by this generation. It is not a light-weight matter. The etiology is multifactorial and complex, and millions are being spent to find the specific causes, to connect the dots and to elucidate a better understanding. The day this happens, we will be enroute to finding that magic pill that will lead to the cure of this dreaded disease called Obesity.

(The writer is a noted bariatric and laparoscopic GI Surgeon, Mumbai)

References:
1.Blanca M. Herrera and Cecilia M. Lindgren. The Genetics of Obesity. Curr Diab Rep. 2010 Dec; 10(6): 498–505.

2.Gratacos M, Gonzalez JR, Mercader JM, et al. Brain-derived neurotrophic factor Val66Met and psychiatric disorders: meta-analysis of case-control studies confirm association to substance-related disorders, eating disorders, and schizophrenia. Biol Psychiatry. 2007;61:911–922. 

3.Willer CJ, Speliotes EK, Loos RJ, et al. Six new loci associated with body mass index highlight a neuronal influence on body weight regulation. Nat Genet. 2009;41:25–34.


 

Comment

Very informative article.8

Dr Shubhangi Chavan    2018/05/09 12:24:13

Excellent article...off course I know the write is a renowned surgeon and it's great to see the awareness she is spreading with her knowledge and experiences through her experience over 15 yrs now??

Payal    2018/05/09 09:32:12

Nicely written article which is easy to understand even for nonmedicoes..

Dr.Anuradha S Dnyanmote     2018/05/08 08:15:11

I am also over weight but in my family no one is over weight. I have one sister and she is having normal weight. I do regular workout in gym 5-6 days in a week for 45-60 minutes a day. I eat 3 meals a day. I weight 99kg and my height is 178cm. Can you please guide me mam to loose weight.

Dr.Mukesh Jain    2018/05/08 07:01:43

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