Why Smaller Humans are in Our Future


Samaras Thomas T. Why Smaller Humans are in our Future. Policy Innovation, Carnegie Council 10/20/2014

Evidence for "Less is More" in relation to the human body

In nature, when animals get big, their numbers decline to match the resources available.  Humans are violating this biological rule by producing not only larger beings but more of them. Since larger people (taller and heavier) require much more of virtually everything, we are aggravating resource, food, and water shortages, and accelerating environmental damage. We are thus faced with a hard choice: do we control the process of getting smaller in a rational way or do we avoid action and let nature take its painful course?

The gerontologist, Dr. Comfort, noted that within the same species, smaller individuals tend to live longer than bigger ones. I have studied the ramifications of increasing body size on a variety of factors related to our health, performance and survival for about 38 years. Based on these findings, I have concluded that the increasing body size of humans is a threat to our survival and quality of life.

Even though conventional wisdom holds taller height as if it was a “sacred cow,” this belief is based on many years of prejudice and a variety of limited scope studies showing that taller, heavier people are healthier and smarter. Although I agree that we have grown taller and heavier due to increases in food availability, improved sanitation, better medical care, incredible advances in medical science and improved standards of living are the real factors that have promoted greater life expectancy at birth over the last 150 years. While our increased body size correlates with the reduction of many diseases and a longer life expectancy, this correlation does not prove that taller, heavier bodies are good for survival of the human race. In fact, my research over the last four decades indicates that there are many benefits to being smaller if smaller body size is not due to malnutrition, congenital defects, poor living conditions or disease. For example, Okinawans are shorter, healthier, and live longer than the average mainland Japanese who live longer than almost all world populations, including the tallest countries.

I am not alone in the belief that increasing height is not a blessing. For example, the famous anthropologists, Ashley Montagu and CL Brace, reported that we have a false belief that we are creating a better breed of people because we are producing larger children. In addition, the medical researcher, ARP Walker, stated that maximizing growth reduces health and longevity. Peter Farb, a former consultant to the Smithsonian Institute, also observed that our increased height and weight are not due to better nutrition but to excess nutrition. Geoffrey Cannon, former chairman of the National Food Alliance, in his book The Fate of Nations stated that rapid growth, early menarche and greater adult height increase the risk of breast cancer….” He disagrees with the principle that accelerated growth equals health and that animal protein is the master nutrient. In fact, he states that these two factors have had disastrous results.

In the July 2011 issue of World Nutrition, an editorial pointed out that the eminent Professor John Waterlow stated: “We will have to accept that future generations will be smaller, leaner, and perhaps slower….The declaration in the UN Convention on Human Rights that all people have a right to fulfill their genetic potential, does not seem realistic if the race is to survive.” The idea that we should attain our genetic potential may be right sometimes, but it is obviously wrong when it comes to attaining a weight of 300 pounds or having individual males produce hundreds of children because they have the genetic potential to do so. I certainly believe this is also true for increased height and associated increases in muscle, bone and fat.

In the near future our genetic potential for height will be subject to genetic manipulation by medical practitioners. With the high value our society places on tallness, this manipulation will assuredly lead to even taller people. If parents continue to want their children to be taller than average, what height will we eventually decide is tall enough?

Certainly taller people enjoy a number of benefits in our society, including higher socioeconomic status, better education, improved opportunity to succeed, physically stronger, and perceived to be more socially desirable. Most of these benefits are related to social bias and are culturally driven. However, if we look at body size objectively, my research indicates that smaller people can be highly creative, productive and athletic. In addition, they require fewer resources and less food, water and energy to function within the same lifestyle as taller, proportionately heavier people. Growing human needs, driven by increased body size, are substantial; the degree of this growth is illustrated by National Football League (NFL) players who are over 300 pounds. In 1970, there was only one player in the NFL that was 300 or more pounds. In 2009 there were almost 400 players at that weight. There is no doubt that increased human size threatens human survival as described in the book: Human Body Size and the Laws of Scaling: Physiological, Performance, Growth, Longevity and Ecological Ramifications, 2007.

An article in the July 2011 issue of National Geographic magazine reported that: “A crisis is looming: To feed our growing population, we’ll need to double food production. Yet crop yields aren’t increasing fast enough.” The article, however, ignored the fact that increasing body size will make our food shortages even worse because bigger bodies need more food at a rate almost proportional to body weight. Over the past 70 years, the average weight increase of American middle-aged males has been about 45 pounds. Assuming that 50% of the population is in the middle age category and that both sexes have increased by 45 pounds, the bio-mass that we need to feed has increased by roughly 7 billion pounds in the US alone.

Another consumption example is provided by CDC researcher, Dannenberg, who found a mere 10 pound increase in average US weight requires an additional 350,000,000 gallons of airline jet fuel per year. Since 1940, our weight has increased by 4.5 times the weight used in his analysis. My own analysis has found that a future US population of 10% taller people with the same body proportions will require huge amounts of additional food, water, raw materials, farmland and energy. For example, we would need an additional 400 million tons of metals, minerals and plastics per year.

Most of us are worried about the trend towards greater and greater weight. However, I don’t think we have grasped the threat magnitude of the obesity  epidemic and associated health problems. For example, The World Almanac, 2011, reports that since 1960, US health care costs have zoomed from $28 billion to $2241 billion in 2007. That’s 80-fold increase in health care costs. The Department of Health and Human Services estimates that we will spend 35.3 trillion dollars from 2010 to 2019. Obviously, this is not a sustainable economic trend. Therefore, we must take strong action to reduce excess weight and associated health problems. A new paradigm for action is proposed next.

While the obesity epidemic is a major national and world problem, we are not doing well in dealing with it. In fact, our children today are more overweight and obese than in previous years. One possible cause for this is increased birth weight. According to a 2007 report by the World Cancer Research Fund, increased birth weight is also correlated with adult height. Freedman and his associates found that young children who were tall had 5 times the risk of becoming obese adults compared to children who were shorter than average. Thus, excess childhood and adult weight is a by-product of the promotion of rapid growth and increased stature.

Studies have found that greater birth weight increases the risk of later overweight and obesity. Since the mother’s height and body weight are tied to increased birth weight, it appears that the obesity epidemic starts with maternal body size and her child’s birth weight. Birth weight and rapid infant and childhood growth rates are sacred cows in medicine, and few researchers are willing to deal with this issue. However, Professor Singhal, of the University College London, has warned that promotion of catch-up or accelerated growth promotes later chronic disease in adulthood. Jonathan Wells, a UK childhood nutrition researcher, also reported that maximizing growth can increase cardiovascular disease. It is clear that as long as we believe that greater height and body size are desirable for our children, we will block real progress in fighting the obesity epidemic because over nutrition starts with the mother and continues through childhood.

Other undesirable aspects of increasing body size are related to the nutritional practices developed during the Industrial Revolution. Professor Barry Popkin’s in his book, The World is Fat, stated that the food system developed over the last 150 years has been devastating to our health. In addition, the 2007 report published by the World Cancer Research Fund reported that we have experienced increased chronic disease along with growing height and weight during the Industrial Revolution. Based on the largest nutritional study ever conducted, Professor Campbell, a specialist in nutrition and protein consumption, reported in his book, The China Study, that animal protein promotes greater height and chronic disease. A report in the Tufts University Health and Nutrition Letter also stated that red and processed meats promote cardiovascular disease, cancer, diabetes and all-cause mortality. What do all these facts mean? They indicate that a major re-evaluation of eating habits needs to be conducted by nutritional scientists, the food industry, non-Governmental organizations and the Government. Failure to take effective corrective action will lead to economic collapse since we can’t afford the level of morbidity and obesity that will result in the coming decades.

Some may argue that obesity has nothing to do with our diet but rather the lack of individual control over our eating habits. Well, health practitioners have been working on this approach for over 30 years without success. It’s time to take a look out side the box and pay attention to the famous physician and researcher, Dr. Denis Burkitt, who reported in his 1994 book, Western Diseases, that we have had an “explosive rise” in Western chronic diseases during the 20th century. Increased chronic disease has grown along with the increased consumption of animal products and processed foods. In addition, lots of data show people in less developed populations who follow traditional, plant-based diets do not suffer from our chronic diseases and retain lower height and body weight, with little obesity being observed. Centenarians in areas known for exceptional longevity (referred to as Blue Zones) tend to follow plant-based diets, with only occasional consumption of meat. My studies have also found that most centenarians are short and lean; e.g. in Northern Italy, it was found that male centenarians were about 5'1" in their youth.

Epidemiologists and demographers support the taller is healthier thesis based on many studies in developed countries. However, we know that taller people tend be from higher socioeconomic classes and tend to be leaner than lower economic class shorter people. These are important health advantages for taller people. However, there is a large body of research that shows shorter, smaller people are quite healthy and live longer. For example, I have found shorter baseball players, football players and basketball players tend to live longer than their taller peer groups. In addition, Professor Dennis Miller studied about 1700 deceased people in Ohio and found that shorter people lived about 1.2 years longer for each inch of reduced height.

I also looked at the death rates of various ethnic groups in the US and found that shorter ethnic groups had lower death rates. The US Government report, Health, United States, 2001, showed that Asians had a much lower mortality throughout their lifetimes compared to Whites and Blacks. Latinos and Native Americans fell in between in mortality. While the report did not give height data, other sources indicate that Asians are the shortest, Latinos and Native Americans somewhat taller, and Whites and Blacks the tallest. Thus, mortality rates rose with increasing height. The report was based on about 18 million deaths over a 14-year period.

A 1991 study by researcher Holzenberger and his associates found that shorter men in Spain gained about 1.8 years with each inch of decreased height. This study was based on 1.3 million men tracked from their youthful ages over a 70-year period.

Recent research by Professors Poulain and Salaris in Sardinia found that as the height of various regions declined, the average longevity increased. They also found the best longevity occurred in a village, Villagrande Strisaili, and the men in this village were the shortest of all the Sardinian regions. They averaged 5’3”. In addition, the researchers found that longevity of a shorter cohort increased by 2 years compared to a taller cohort.

Interestingly, among developed populations, Andorra, Macau, Japan, San Marino, Singapore, and Hong Kong had the highest life expectancy compared to the six tallest populations in Western Europe: Scandinavians, Netherlands, Germany and Finland.

I published an interesting finding in Experimental Gerontology in regard to life expectancy at birth for US men and women born around 1980. Men were 9% taller and had a 9% lower life expectancy. I have found similar results in other populations as well. In addition, the men lost 1.3 years per inch compared to women. So the height–longevity factor appears to apply when men are compared to women. Professor Rollo also found that the difference in longevity between male and female rodents was eliminated when he adjusted for the difference in their weights. Professor Miller's study of deceased Ohio men and women found that they had about the same life spans when men and women of the same height were compared.

Animal studies generally confirm the relationship between smaller size and longevity. For example, small dogs live longer than big dogs and small male dogs live longer than bigger female dogs. Smaller horses also tend to live longer than bigger ones. Smaller Asian elephants live longer than larger African elephants.

In developed countries the majority of studies show that taller people have less coronary heart disease. However, as mentioned before, the advantages of improved socioeconomic conditions, leaner body mass, and better nutrition (less junk food and more vegetables and fruit) can explain this finding. In contrast, a number of studies have found people in non-developed populations have little to no coronary heart disease and strokes. For example, the island of Kitava has been studied for 10 years and no evidence of heart disease or stroke was found among these short people (males average 5’4”). The population has a primarily plant-based diet and is moderately active. A number of other 20th century studies have also reported no coronary heart disease in the Cook and Solomon Islands, Papua New Guinea, the Kalahari bushmen, and Congo pygmies.  All these populations were short by Western standards. To my knowledge, no Western countries can duplicate these findings. However, during the early 1900s, Western countries had much lower coronary heart disease than they have now and they were a few inches shorter than we are now. Of course, shorter women have lower heart disease than men in Western countries. However, Li reported that some populations show no difference in heart disease between men and women. Height differences were not given but I suspect the differences are small.

Many studies indicate that we should eat less. Yet, many medical practitioners balk at the idea of feeding children less than we currently do. However, the World Cancer Research Fund reported that energy restriction is a proven way for reducing the diseases of old age. For example, Okinawans eat about 20% fewer calories than mainland Japanese and 40% less than Americans. They outlive both the mainland Japanese and Americans. Okinawans also have one the world’s highest percentage of centenarians. Dr. Andrzej Bartke, a leading expert on caloric restriction, reported in Human Body Size and the Laws of Scaling that the ability of caloric restriction to delay aging and increase longevity is highly consistent across a variety of species, including dogs and non-human primates.

Dr. Vallejo put patients on a normal calorie diet one day and a 50% lower calorie intake the next day. The patients on this program had a substantially reduced mortality compared to a control group that ate normally. Professor Willcox studied a few thousand elderly Japanese men living in Hawaii and found that those who ate fewer calories had a lower mortality in subsequent years. However, men who ate less than ~1000 kilocalories started to see an increased mortality. So there is a lower limit that negates the benefits of caloric restriction. Another researcher, Dr. Fontana, has been studying humans that are on calorie restricted diets and has found that they are less prone to old age diseases and, of course, obesity. Burkitt and Temple, in Western Diseases, reported that during the lean years of WW II, Europeans saw a steep drop in all-cause mortality. Studies with non-human primates have also found that calorie restricted monkeys have lower death rates as well as healthier biomarkers. Caution: anyone planning to go on a calorie-restricted diet needs to be under the supervision of a professional nutritionist and his/her physician.

A 2009 study by Granados and Roux found that mortality dropped during the Great Depression and life expectancy for people born during this period increased sharply compared to earlier and subsequent periods of economic improvement. Surprisingly, infant mortality also dropped. It is certainly unexpected to see a period of deprivation lead to improved health but that appears to be the case. Thus, abundant nutrition and economic prosperity do not always lead to improved health and longevity. This indirectly supports the benefits of a reduction in food intake. This conclusion is supported by data from famine studies which show adults subjected to famine during gestation either had no decline in adult mortality or actually saw an increase in longevity as found by Song for the Great  Leap Forward Famine.

One of the big arguments favoring taller, bigger people is that they are more productive and intelligent. There are studies showing a modest difference in IQ scores between taller and shorter children. The rationale behind these findings is that better childhood nutrition, as reflected by greater height, and a bigger brain reflect greater intelligence. My conclusion, delineated in a book I edited, Human Body Size and the Laws of Scaling, is that height per se doesn’t affect intelligence. If height was related to intelligence, men would be smarter than women but recent studies indicate more women are graduating with higher degrees from colleges and universities than men. Also the Japanese would be less intelligent than Caucasians. But this is not true as well. The ancient Greeks and Romans appear to have been quite intelligent in spite of their short stature. The differences in brain size between big and small dogs is much larger than between big and small humans. Yet, I found no relation in intelligence between small and big dogs.

Great achievements are not foreign to short and shorter than average people. In fact, if we had height data for great achievers over the last 4000 years, they would most likely be shorter than the average American male. For example, in business David Murdock, Andrew Carnegie, Aristotle Onassis, Ross Perot, and Mayor Bloomberg have been very successful in acquiring wealth. In science, Nobel prize winners in science and medicine include Millikan, Einstein, Michelson, McClintock, Charles Steinmetz, and Buckminster Fuller. In music, we have Mozart, Mahler, Beethovan and Stravinsky. Famous artists include Michelangelo, Picasso, Joan Miro, Thomas Benton, and Salvador Dali, and Toulouse Lautrec.

In terms of physical strength and reach, tall people definitely have an advantage. They make better basketball and football players, pitchers, short distance runners, and swimmers. However, shorter people are better figure skaters,  gymnasts, long distance runners, and divers. They are also good martial artists, boxers, and wrestlers within their weight classes.  Shorter people are actually stronger in relation to their weight, have faster reaction times, are more agile and can accelerate their limbs faster.

Why should we change our thinking about taller and bigger human size when so many epidemiologists and demographers think it reflects better health?  A professor of medicine once told his students that half the information that he taught them was incorrect. The problem was he didn’t know which half was wrong. It wasn’t that long ago that we laughed at a few pioneers who told us bacteria cause infections and disease. We were also told heart disease had nothing to do with diet and smoking wasn’t bad for us. More recently, an Australian researcher was ignored when he reported that ulcers were primarily related to a bacterial infection rather than to stress. Many sacred cows have been destroyed throughout human history. Failure to objectively re-evaluate our promotion of rapid and greater growth in our children is no different than our previous failures to recognize alternative solutions to our health, social or environmental problems.

These findings should not promote angst in taller people. Height is only 5 to 12% of the longevity picture when looking at populations of tall and short people. In addition, on an individual basis, relative weight, genetics, exercise, smoking, diet, medical care, socialization, stress, education, economic status and lifestyle are more important in how well and how long you live. And there are tall people who live well into their 90s—the economist, John Kenneth Galbraith (6’8”), lived for 98 years.

As mentioned before, Professor Waterlow has recommended a smaller human size to improve our chances of survival. We need to follow up on his suggestion with a systematic evaluation of larger body size and its risks to human happiness and survival to determine how the world should approach the problems related to human growth. This effort would include:

  1. Revised nutrition guidelines,
  2. Nutrition clinics for new mothers,
  3. New portion guidelines
  4. Intensive educational programs

A population of somewhat shorter and substantially leaner people can’t hurt, and may make the world a significantly better place for all of us.