Don't know if this is actually true, but it fits my anecdotal observations, and I wouldn't be surprised if it is empirically true. It also correlates to the much higher incidence of diabetes and heart disease in immigrants than in either India or the US, which is backed by data.

Here's the rough explanation, which I am pretty confident is correct. I'll talk about diet and health generally, since height is a consequence of that.

Us FOB Indians, unlike American-born ones, are raised on a high-carb/low-protein traditional diet. Immigrants like me typically switch to an even worse diet when we come here. Even the meat-eaters. Not good for healthy physical development.

The disease stuff is a consequence of poorly adapting Indian diets to the American environment I think (for example, vegetarian Indians coming to the US and eating far too much pizza/sugary crap/bread because it is not exactly easy to replicate the slightly better traditional diet... when we eat out in Indian restaurants, we overeat the very unhealthy Punjabi or South Indian cuisines, since the broad variety of Indian regional cuisines is mostly not available in the US).

Much as I love the stuff, to the point of addiction, Indian cuisine is probably the worst in the world as far as grain-based high-carb food goes. To the extent that Jared Diamond is correct in calling agriculture the "worst mistake in the history of humanity," India probably made this mistake in the worst possible way, followed closely by China. It is no surprise that these are the two countries with a) the biggest populations b) the most broadly malnourished ones (thanks to Jane Huang for turning me onto this article):

The Worst Mistake in the History of the Human Race

Indians probably get more calories from grain than just about any other major group. Even sub-Saharan Africans probably eat better, since their carb sources (plantain, cassava, yam) are better than rice/wheat.

Most protein in Indian diets comes from lentils which is only about 22% or so protein in the typical case for the major Indian lentils (toor, chana, masur, moong and urad dals). Dairy is a key part of all diets, vegetarian or not, but we don't consume enough of it.

I've been trying to slowly develop a more low-carb/high-protein Indian diet for myself, but it's pretty darn hard. Making progress though. Key is to cut out the wheat (roti, naan), limit the rice and potato, and up the yogurt, greens and dal. Especially the higher protein lentils like black chick peas which are not as commonly eaten as the lower-protein ones. I've been slowly trying to reinvent a lot of my favorites in high-protein/low-car forms.

My goal is to transition the Indian part of my diet (which is significant, since it is my favorite) to an approximate paleo-vegan-version within the next year.

In general, Indians of all classes in India are kinda malnourished. The poor people because they are poor and cannot afford a lot of protein (I'd say most typical poor people are at least 6 inches shorter than their genetic limit), the rich because they eat poorly despite being able to afford a better diet, out of a mistaken belief in the traditional diet and an increased ability to eat more of the worst of it while doing far less physical work (higher disposable incomes for the middle class means more eating out and more of the unhealthiest traditional stuff: samosas, puris, dosas, alu parathas...).

India today is kinda like Japan shortly after WW II: the average male Japanese height went from like 5' 4" to 5' 9" or something in a few decades. Something like that is needed in India, but it will be much harder, because the population is much bigger and unlike Japan, there isn't even a healthy tradition of seafood as a core part of the diet (which, despite my favoring vegetarian/vegan diets for animal rights reasons, are obviously undeniably healthy).

It took me a long time (and unnecessary poundage gain) to understand this situation, because we are so trained to think that "traditional" cuisines are better than "modern" cuisines. True if you're comparing traditional (dal/roti/rice/sabji) to junk food (soda, fries, burger, pizza, samosas...). Not true if you compare traditional to the most thoughtful diets that can be designed using modern scientific understanding of nutrition principles.

Given the size of the Indian population worldwide, and its general popularity among other cultures as well, some restaurant entrepreneur can probably make a serious killing by creating a whole modernist paleo-Indian type cuisine. Keep the spices and flavoring/cooking techniques. Lose most of the main ingredients and replace with alternatives.

Thanks to Jason Ho, Vivek Ponnaiyan, Gregory Rader and Erik Marcus for educating me on this topic.

Thanks to thinking about this stuff more consciously for the last 6 months, I've lost 10 lbs. It's a start. At 38, I obviously can't grow taller than my current 5' 7", but I can hopefully fix the other aspects of my health. Jason has inspired me in particular to try and fix my high cholesterol without medication. Check out his excellent post on the subject:

http://qaboom.com/the-bodybuildi...

Here's to better health for desis around the world.