In this second in a two-part series, HelpingYouCare™ reports on two new scientific papers published in The Lancet medical journal, which focus on solving the global obesity epidemic.
One of these new studies clarifies our understanding of how people lose weight and how fast weight can be lost. The other focuses on science-based solutions needed to reverse the obesity epidemic, and calls especially upon governments to act.
The Alarming Health & Economic Costs of the Obesity Epidemic
In our first article in this series, Obesity Alert: Scientists Warn of Alarming Health Costs, Discuss Cures, we reported on the alarming statistics and projections made by U.S., UK and Australian scientists in the first two scientific papers in The Lancet‘s four-article series. Among their findings and projections were the following:
- Based on current trends in escalating obesity, there will be 65 million more obese adults in the U.S. and 11 million more obese adults in the UK by 2030. This would represent an approximate doubling of the number of obese adults in the U.S. from current levels, and would mean that fully half of the U.S. population would be obese by 2030;
- This will lead to an additional 6 million to 8.5 million cases of diabetes, 5.7 million to 7.3 million cases of heart disease and stroke, 492,000 to 669,000 additional cases of cancer, and 26 million to 55 million “quality-adjusted life years forgone for USA and UK combined;
- The combined medical costs associated with treatment of these preventable diseases are estimated to increase by $48—66 Billion/year in the USA and by £1.9—2 billion/year in the UK by 2030;
- The top contributors to this cost burden are arthritis, coronary heart disease, and diabetes, and about half these costs would be incurred by individuals 65 years and older (further threatening the solvency of the publicly funded Medicare program);
- In addition to these rising health care costs, there will be a productivity loss due to obesity amounting to 1.7—3 million productive person-years in working US adults, representing an economic cost as high as $390—580 billion;
- Globally, rising obesity has become the principal cause of preventable diseases in many low-income countries, and has overtaken tobacco as the largest preventable cause of disease burden in some regions; and
- Unless something is done to stem the global tide of rising obesity, the continuing increases in overweight and obesity in adults are widely projected to continue to heighten the burden of obesity-related death in the coming decades.
What Can Be Done About the Obesity Epidemic?
In the remaining two scientific papers in The Lancet Obesity series,
A. One team of international scientists led by doctors from the U.S. National Institutes of Health (NIH), National Institute of Diabetes and Digestive and Kidney Diseases, examined the physiology behind how weight is actually lost, controlled and maintained, concluding that current assumptions about speed and sustainability of weight loss are wrong; and
B. A second team of international scientists led by doctors from Harvard School of Public Health, examined scientific requirements to solve the obesity crisis, and made recommendations for science-based solutions to reverse the obesity trend, as well as issuing a call to action.
A. Understanding Weight Loss
In Quantification of the effect of energy imbalance on bodyweight, Dr Kevin Hall, of the NIH National Institute of Diabetes and Digestive and Kidney Diseases and colleagues examined how weight loss is achieved.
Working from their conclusion that “[a]ccurate mathematical models of human metabolism are needed to properly assess the quantitative effect of interventions [toward losing weight] at both the individual and population levels,” Dr. Hall and his colleagues challenged the common assumption that doctors and dieticians have made for decades: that cutting 500 calories per day from a person’s diet will result in a steady weight loss of approximately one pound per week.
Dr. Hall and colleagues found that this assumption is in fact not correct and leads to unrealistic assumptions for diets, because it fails to take into account metabolic changes that affect each individual differently during dieting. These metabolic changes occur differently depending upon such factors as a person’s sex, age, height and weight, helping to explain why some people lose weight faster than others, even though they may be eating the same diet or doing the same exercises.
Simulation Model for Weight Loss. Based upon insights about weight loss gained by these scientists from “developing and validating various mathematical models of human metabolism and body-composition change,” Dr. Hall and his team created a new online body weight simulation model which takes into account metabolic changes that occur with decreasing body weight, depending upon the person’s sex, age, height, and weight.
This model, using Java software, can simulate and project more accurately than prior commonly used models the number of calories that a particular individual would need to cut from his or her daily diet and the length of time required for that person to reach a target weight, given a specified level of physical activity and given that person’s sex, age, height, and starting weight. The model also provides the maximum daily number of calories that person can thereafter eat to maintain the target weight. The model can thereby be useful to individuals and their doctors and dieticians in tailoring dietary regimes to the particular person.
For example, let’s assume you are a woman, age 60, 5′ 8″ tall, you currently weigh 185 pounds, and you want to lose 55 pounds to get down to 130 pounds. Here is an example of how you could use the simulator, and what you would learn:
You then enter your desired target weight and the length of time you want to diet to reach that goal. In this case, if you enter that your goal is 130 pounds and you want to reach that goal in 180 days (6 months), the simulator tells you that you cannot reach that goal at your current activity level within 180 days. If you leave your activity level as is but increase your dieting period to 240 days (8 months), the simulator tells you that you would have to eat only 287 calories per day for 240 days to reach your goal — which would be unhealthy and unsustainable. Finally, if you leave your activity level as is and enter 365 days of dieting, the simulator tells you that you can reach your goal of 130 pounds (losing 55 pounds) by eating 1,065 calories per day for 365 days.
The simulator explains that in your case, at your current activity level, this means you would have to cut 2,024 calories per day from the amount you are currently eating, and stay on that 1,065 calorie per day diet for 365 days to lose 55 pounds and reach your target weight. After that, to maintain your weight, you can eat no more than 2,349 calories per day, at your current activity level.
With advice from your doctor, you may determine that a 1,065 calorie diet for 365 days is too severe, and not realistic. With your doctor’s advice, you can then use the simulator to help you adjust your activity level and length of time to reach your target weight, until you arrive at a healthy, sustainable, and realistic diet plan to reach your target weight.
The simulation model thus helps a person gain a more realistic perspective on what will be required in your particular case to reach your desired weight. Starting with realistic expectations and selecting a diet level that you can realistically sustain for the required period of time may be the key to staying on your diet.
The simulation model demonstrates that people with greater body fat initially lose weight faster than those with more lean tissue and less body fat to lose. This is because greater expenditure of energy is required to burn lean body tissue than to burn body fat, due to complex “underlying physiological mechanisms” that “involve the regulation of metabolic fuel selection.” However, reaching a stable body weight will naturally take longer for those with greater body fat to burn than those who weigh less at the start of their diets.
Rule of Thumb for Weight Loss. Based on their model, Dr. Hall and colleagues derived a rough dieting rule of thumb for a typical overweight adult, which is more accurate than current assumptions referenced above. Their rule of thumb is that every 10 calories per day reduction in energy intake will result in a body weight loss of about 1 pound over about 3 years, with half of that occurring in the first year.
This would mean, for example, that cutting out a habit of eating a 220-calorie donut every day, without making any other changes in one’s diet or exercise, would result in losing approximately 22 pounds of weight over three years, with 11 of those pounds being lost in the first year on such diet. This is a more realistic prediction than the 78-pound weight loss in three years that would be predicted by the old dieting assumption referred to above.
How does added physical activity affect the equation? Based on their model, Dr. Hall and colleagues also discovered that running roughly an additional 20 km per week at a moderate pace would initially result in “slightly more rapid and greater predicted weight loss compared with an energy-equivalent reduction of food intake.” This, of course assumes, that one does not compensate for the energy expended in running by eating more.
“Increased physical activity versus an initially energy-equivalent reduction of food intake leads to differing predicted weight loss because the energy expenditure of added physical activity is proportional to bodyweight itself,” they explain.
“However,” the authors state, “as the magnitude of each intervention [dieting and exercise] increases, there is a point when diet leads to greater weight loss than does physical activity.” They call for further research to understand the exact dynamic relationship between energy expenditure through exercise and reduction of energy intake through dieting in effecting weight loss during the course of a diet.
Societal Implications for Reversing the Obesity Epidemic. The authors discuss other research findings indicating that an energy imbalance of only 10 calories per day has caused the 20-pound increase in average adult weight that has occurred in the U.S. over the past 30 years. However, they caution that this does not mean that a similar very small reduction in overall calorie intake could reverse the obesity epidemic.
They explain that the equation is not that simple, because in order to maintain their higher average weight, which has itself required greater energy expenditure, people have actually had to increase their daily calorie intake by an additional 220 calories to compensate for the greater energy expended due to the higher weight.
This means that in order to return to the average body weight that prevailed in the USA in 1978, obese adults (the 14% of the U.S. population with a BMI greater than 35) would actually have to cut their calories by more than 500 calories daily. This amount of weight loss would take approximately three years for those moderately obese, and longer for those that are more obese.
In conclusion, the authors write:
B. Solutions to the International Obesity Epidemic
In the last of the four articles in The Lancet‘s Obesity series, Changing the future of obesity: science, policy, and action, Prof Steven L Gortmaker, Department of Society, Human Development, and Health, Harvard School of Public Health in Boston, and colleagues examined the need for science-based models to find realistic societal solutions to the global obesity epidemic, and called upon governments and the UN to take a greater role in combating the obesity trend.
The authors first refer to findings similar to those discussed by the other papers in The Lancet’s Obesity series. “Childhood and adult obesity is increasing in countries of high, middle and low income,” they write. “A growing body of evidence links obesity to short-term and long-term health, social, and economic consequences.”
“The changes needed to reverse the epidemic are likely to require many sustained interventions at several levels,” the authors observe. They state:
The number of suggested interventions, plus the contested nature of potential solutions, can create a “policy cacophony”, which makes the task of obesity prevention appear hopelessly difficult. However, applications of quantitative modelling have helped to develop a new science base that provides insights into the dynamics of this epidemic, and brings together different evidence and approaches.”
The Need for Scientific Understanding of the Problem and Science-Based Approaches to Solving It. They then make a series of key findings regarding the need for scientific data and scientific analysis to determine, at a macro or societal level, what will be needed effectively to combat the worldwide obesity epidemic:
• Mathematical modelling provides important insights into the causes and dynamics of weight gain and loss. The energy gap framework provides a common metric for translating changes in dietary intake and physical activity into weight change.
• Comparative effectiveness and cost-effectiveness policy and programme analyses indicate that several are both effective and cost saving.
• The application of a systems approach to obesity prevention is novel but already has policy implications including: the need for multiple actions especially in non-health sectors, investments in cross-cutting support systems, policies that target the food and built environments, and additional data for forecasts and evaluation.”
Need for Action by Governments and the UN. The authors advocate that solution to the worldwide obesity epidemic, which will require addressing the underlying economic and societal drivers that have led to this trend, can only be achieved through government involvement, as well as involvement of multi-national organizations such as the U.N. Two of their key findings are:
• The UN High-Level Meeting on non-communicable diseases in September, 2011 is an important opportunity for the international community to provide the leadership, global standards, and cross-agency structures needed to create a global food system that offers a healthy and a secure food supply for all.”
Cost-Effective Solutions. Citing a number of studies that have been conducted to assess what are the most-cost effective means of combating obesity, including Australian Assessing Cost-Effectiveness (ACE) in Obesity and ACE—Prevention studies, the authors observe:
“Even the most effective interventions will not be sufficient to reverse the obesity epidemic individually. Solutions need to be multifaceted, with initiatives throughout governments and across several sectors,” the authors conclude.
A Multi-Sector Call To Action. Professor Gortmaker and his team issue a “Call to Action” to governments (which, they say “are the most important actors in reversing the obesity epidemic, because protection and promotion of public goods, including public health, is a core responsibility”), to international agencies such as the UN, as well as to the private sector, saying:
In addition, they call on medical professionals to help individuals improve diet and physical activity, and they call on public interest and consumer associations, charities, academic institutions, foundations, professional associations, and other community, religious, and advocacy groups to continue “lobbying for healthy, sustainable, and fair environments.”
Finally, the authors observe, “The final choices for eating behaviours and physical activity rest with individuals, although in many environments the available options might already be limited.” “Parents and caregivers,” they say, “have particular responsibilities and greatest opportunities to promote life-long healthy behaviours among children and adolescents.”
In conclusion, Professor Gortmaker and colleagues state:
See the first article in this two-part series by HelpingYouCare™, entitled Obesity Alert: Scientists Warn of Alarming Health Costs, Discuss Cures
See also previous HelpingYouCare™ reporting on:
MyPlate Icon Replaces Food Pyramid (with links to the new Dietary Guidelines for Americans issued by USDA and HHS).
Copyright © 2011 Care-Help LLC, publisher of HelpingYouCare™.