The state of obesity in India

Obesity is closely related to where in the "nutritional transition" a family is. Surprisingly, the relationship between the two is a bell curve, not a straight line.

Following the path of many developing nations, India's population of overweight and obese people has been increasing steadily. It is estimated that 14% of the world's overweight people live in India, which is beginning to catch up to the fraction of the world's population living inside its borders (17.5%).

The Indian state and healthcare system has historically been focused on a very different set of diseases. Communicable diseases such as polio, malaria and measles have been on top of its agenda. At the time the Indian state came into being (and for many years afterwards), this focus was warranted. Communicable diseases have been a bugbear of tropical and semi-tropical regions for a long time. Any investment into this area would have had the best cost/benefit ratio in the short to medium term. To make matters more complicated, this had to be done while simultaneously creating a public health system which benefitted all. That the country made any progress at all is a minor miracle.

This led to the neglect of other aspects of healthcare, especially diseases of the non-communicable variety. This was not a major factor in the case of obesity, because obesity and overweight were not major problems in the country for a long time. Unfortunately that is now starting to change. Obesity has doubled in the country between 2005 and 2015, and the problem is not limited to urban and educated areas of the country. Rural areas have been seeing similar gains to urban areas.

The transition to a better life

To understand the reasons behind what is going on in the country, Aiyar, Dhingra and Pingali (2021) looked at data from the Indian National Family Health Surveys held in 2005-06 and 2015-16. They modelled various variables in order to extract a causal chain for what is going on.

Some baseline figures before we delve into obesity. Fertility rates are close to replacement levels across the country. In other words, India's population has begun to plateau. The consumption of alcohol and tobacco has both decreased, as has the frequency of physical exercise such as walking. The average Indian watches more television than she ever did, and more people own cars and bikes than ever before. People are also eating a more diverse diet across the country. This ties in with the greater socioeconomic prosperity observed across the country. The average Indian is also older and greyer than she used to be.

Somewhat unsurprisingly, the authors find that obesity incidence is linked to the state of the nutritional transition a family is in. What exactly does one mean by nutritional transition? A nutritional transition occurs when the kind of nutrition a family gets changes due to a rise in socioeconomic stature. So the transition from subsistence agriculture to working in a garment factory may be the start of a family's nutritional transition because the family switches from eating food it produces to processed goods bought in a market. In our example, this process reaches its end around the time when a child completes university and joins an IT company. The family might make multiple switches in food sources during this process, all of which fall under the term "nutritional transition."

What was somewhat surprising to me, though, is that the incidence of obesity follows a bell curve. The beginning of a family's nutritional ascendance is associated with an increase in obesity, which begins trending downward again during the later stages.

As it turns out, there is literature on this topic which gets into detail about this phenomena. It is mainstream thought that during a country's nutritional transition, obesity risks increase amongst poorer populations and decrease in richer populations. This is caused by a transition from labour-intensive work in agriculture to more sedentary work.

Lest one believes that this is limited to men, the number of women working in these sedentary jobs also increases. The opportunity cost of women not participating in the workforce tends to be too high for them to not shift to doing some work, be it sitting in shops, manufacturing something in factories, or more service-oriented work in general. This gets combined with relatively cheaper high-energy density processed foods, leading to an increase in overweight incidence.

The rich tend to avoid this through greater dietary diversity, more leisure time, and increased physical exercise. To understand this phenomenon, a conceptual model was developed which formalised the factors leading to an "obesogenic" environment. This environment is created due to certain biological, socioeconomic, cultural and transportation factors.

The biology of obesity

Aiyar, Dhingra and Pingali add to that model by adding risks arising from reproductive stress and the age at which the socioeconomic transition occur. Reproductive stress can be thought of as the strain placed on the body due to childbirth. Quite obviously, this only applies to women. The more the number of children one gives birth to in a given time frame, the greater the reproductive stress on the body. The greater the reproductive stress, the lower the chance of obesity.

The other biological factor is age. BMI is positively correlated with age. The older you are, the higher your BMI is, generally. This can be due to either no change or an increase in nutritional intake coupled with a decrease in physical activity.

Both these factors couple together as well. Typically, younger women tend to have greater reproductive stress during the early parts of a socioeconomic transition. However, as the socioeconomic transition progresses, the average age at which women have children increases. Fertility also decreases. Women begin to space their children out more. Access to contraceptives leads to fewer accidental pregnancies. This leads to a decrease in reproductive stress, causing a corresponding increase in BMI. As one can expect, being unmarried is correlated with being overweight.

The role of technology

Several technologies contribute to obesity with the motor vehicle and the television being the most prominent examples. The impact of these technologies is very evident during the early part of this transition. This is because people tend to have limited free time at this point and they prefer to use it for relaxation. At this time, the short-term effects of getting some relaxation time trump optimisation for long-term health benefits. Sitting in front of the TV and relaxing is one of the first things a family starts to do as their nutritional transition begins. Since this is a nutritional transition, it is accompanied by a shift in diet to high energy density foods.

This is also the time at which appliances like gas stoves, washing machines and microwaves start popping up in these homes. The influence of these appliances is typically felt amongst the female members of the household, leading to a greater incidence of overweight amongst women as compared to men.

On the other hand, the acquisition of motorised transport tends to play a greater role for men, at least initially.

Behaviours that generate obesity

Coupled with technology are behaviours the authors classify as obesogenic (generating obesity). These behaviours included watching television, binge eating and binge drinking. Smoking is an anti-obesogenic behaviour. At the beginning of a nutritional transition, both men and women are more likely to smoke, less likely to binge drink, and less likely to binge on fatty foods.

This starts changing as the nutritional transition chugs along. People start smoking less, eating more fatty foods, and binge drinking. As the transition reaches its tail end, one sees this behaviour start trailing off as individuals begin prioritising long-term health goals over short-term fulfillment.

Interestingly, one finds dietary diversity weakly correlated with a reduction in overweight amongst rural women.

The role of socioeconomics and health environment

During the earlier stages of a nutritional transition, overweight incidence is associated with higher socioeconomic status. This is especially pronounced in Indian households, because women tend to face higher barriers to food access than men. When socioeconomic conditions ease up, they see a greater increase in obesity.

As the nutritional transition continues, following the bell curve, we see individuals start to make the shift to the prioritisation of long-term goals over immediate benefits.

However, overweight indicators tend to be highly correlated with development indicators. Low-productivity agricultural states are at the earliest state of the nutritional transition. States with high agricultural productivity are somewhere in the middle. Rapidly transforming areas are at the last stages of their transition and tend to be rapidly urbanising. In India, because most states are agricultural, education tends to be positively associated with obesity.

It is not just development indicators which affect one's weight. Women from minorities tend to have greater incidence of overweight, and women from scheduled castes and scheduled tribes (SC/ST) tend to have lower rates of overweight incidence. While the authors do not speculate overmuch about this, it may be inferred that minorities may be further along the road of nutritional transition than majority families, and SC/ST families tend to not be as far along this road.

All these factors combine with genetics, over which one has little control, and a person's intrinsic and mental health to produce a colourful picture.

The mosaic of obesity in India

One of the most interesting points highlighted by the authors is the difference between rural and urban citizens, and between men and women. Rural women have seen the greatest increase in overweight incidence between the two rounds of the NHFS analysed in this study. However, urban men have seen a greater increase  in overweight and obesity incidence compared to rural men.

Why does this discrepancy exist between overweight incidence in men and women? Part of the reason is that obesogenic factors contribute more than socioeconomic stressors for men, while it is the other way around for women. The authors do not speculate overmuch about why this might be so, but certain dots have been provided which can be connected. Women tend to be more marginalised than men in terms of access to resources and food.

The discrepancies between urban and rural women are largely explained by the reduction of significant reproductive stress amongst rural women. Urban women already had low reproductive stress, for fertility rates were already near replacement rates in urban areas.

The one factor which remains a significant factor for all groups is community incidence. If you live in a community with high overweight incidence, you are more likely to be overweight yourself. This cuts across all lines, whether they be of gender, caste, or the urban-rural divide.