Fifty years from now, if current trends persist, obesity will be up there with climate change and water shortage as one of the biggest problems facing India.

There is something very real about obesity-linked diseases and their prevalence in India. We have the world's largest population of diabetics and this number - already at 37 million - is set to more than double in the next 25 years, according to the World Health Organisation (WHO).

A study by a Canada-based professor of medicine warns that by 2010 nearly 60 percent of the world's heart patients will be in India. School surveys have shown that 30 percent of adolescents in our cities are already overweight. As these adolescents reach adulthood they will add to the spiralling numbers of diabetics, heart patients and hypertension sufferers.

Imagine the impact of this on the healthcare system. Given that we have just marked World Diabetes Day (Nov 14) and India's eighth Anti-Obesity Day will be held Nov 26, it is a good time to pause and consider how what we eat today is shaping our nation's tomorrow.

As a rapidly developing country, India has a poor prognosis for its growing obesity problem. Globally, the link between economic development and nutrition transition has been amply proven.

Prakash Shetty, of the Food and Agriculture Organisation (FAO), says lifestyle and food habits change as an economy develops. There is a significant increase in the consumption of fats, sugars and energy-dense foods. The main drivers behind changing lifestyle and food habits are rising incomes, urbanisation and globalisation.

Rising incomes and urbanisation lead to the substitution of servants or appliances for physical work around the house, while family breadwinners take to desk jobs instead of ploughing the fields. These factors also encourage more sedentary pursuits such as television viewing and computer use, and well-off city-dwellers travel by car instead of walking or cycling.

At the same time, globalisation puts junk food and fast food within easy reach of a population often hard-pressed to find time to cook healthy meals, but with more than enough money to buy a greasy lunch at a nearby restaurant.

In India, these factors have contributed to the rise of bad eating habits and lack of exercise amongst a growing urban middle class, and their effects are startlingly visible. A University of North Carolina study conducted in Andhra Pradesh showed that 37 percent of women living in cities are clinically overweight or obese, and a study by the All India Institute of Medical Sciences (AIIMS) found that 76 percent of women in Delhi suffer from abdominal obesity.

But India's obesity crisis has been further exacerbated by some peculiarly Indian factors. Despite India being a vegetarianism stronghold, the average Indian's diet severely lacks fruit and vegetables - an abysmal low of 150 gm a day against the WHO recommendation of 400 gm a day.

Instead, our calories come mostly from refined carbohydrates and fats. Indian food also tends to be amongst the most oil-rich in the world, and while we have taken Western junk food to heart (quite literally!) we have our own array of fried snacks (think pakoras, samosas and vadas) which make us susceptible to weight gain without even factoring in globalisation.

To add to this dismal picture are schools which promote a culture of fierce academic competitiveness and leave children with no time to play or exercise. That we are as an ethnic group more genetically prone to obesity and its health consequences is the cherry on top. Indians have up to five percent more body fat than Caucasians at a given weight and height, suggesting that we may face higher health risks than we expect at our weight. Some researchers have even gone so far as to suggest that Indians are genetically more likely to store fat due to a 'thrifty gene' that evolved out of undernourishment in the past.

Given the enormous impact obesity and its associated diseases are going to have on our already strained healthcare system, our economy and most importantly our national well-being, it is strange that obesity does not make it to the agenda of Indian public health policy in any significant way.

Once again this can be traced to our history of undernourishment. Amidst poverty and deprivation, the words fat and prosperous are synonymous. Many are still unaware that too much fat can be a dangerous thing. In addition, healthcare providers and policymakers in India are historically used to dealing with undernourishment.

This is not to say undernourishment does not exist in India. It does, on a very significant scale, but this just makes the task of policymakers a dual challenge. The formulation of a broad food policy that encompasses both under- and over-nutrition is the only answer to India's peculiar problem.

In dealing with obesity, we have to shift from treating it merely as a personal problem to tackling it as we would any other public health issue. Given the future trajectory of the obesity epidemic in India, it will be most economical to nip the problem in the bud by attempting to prevent rather than cure.

Instead of expensive weight loss clinics and obesity surgery which only the rich can afford, we must look to large-scale preventive measures such as nutritional education made mandatory in schools and for parents, development of parks, playgrounds and school sports programmes, and sweeping changes to our food environment through legislation and/or government intervention such as banning the sale of junk food in and around schools. We must even seriously consider changing our agricultural and food price policies to encourage the consumption of healthier foods.

Of these measures, the ones that focus on children are likely to yield the best results. Dietary habits last a lifetime and given India's youth-heavy population pyramid, these children could grow up into healthy young adults in the future, alleviating the burden on our healthcare system and, more importantly, living longer and healthier lives.