Diet and Lifestyle Medicine for Chronic Diseases

The 21st century has presented a planetary health crisis. We are living longer than ever before, with a majority of men and women living into their mid- to late seventies; however, along with the expanded life expectancy has come epidemic proportions of chronic diseases. Seventy percent of Americans die each year from chronic diseases with heart disease, cancer, and stroke accounting for more than 50% of deaths annually (1). In 2003, more than half of Americans (162 million cases) had at least one of seven common chronic diseases (cancers, diabetes, heart disease, hypertension, stroke, mental disorders, pulmonary conditions)(2).

Overweight and obesity are most notably on the rise, increasing in the general population from 54.9% in 1988-1994 to 67% in 2005-2006 (3). The health of American children has shifted even more dramatically, with rates of overweight/obesity doubling and tripling compared with the late 1970s to early 1980s. As of 2005-2006, the incidence of overweight/obesity in school-age children ages 6-11 years old was 15% (up from 7% in 1976-1980) and 18% (up from 5% in 1976-1980) in adolescents ages 12-19 years old (3). In fact, an article in the New England Journal of Medicine written in 2005 by Dr. Olshansky and colleagues had commented that life expectancy is on a decline – it has been predicted that children born in the 21st century will not outlive that of their parents if the situation does not change (4).

The implication is that extended chronic diseases will shorten lives, reduce quality of lives for the individual affected and caregivers, and impart a tremendous economic burden (more than $1.5 trillion annually in the U.S.). Furthermore, the U.S. spends more on health per capita than any other country and these expenditures continue to increase.

What can be done to reverse the tide of chronic disease?

If we look to the guidance of opinion leaders like the American Diabetes Association, the American Heart Association, and The Obesity Society, therapeutic lifestyle changes (TLC) involving diet modification and regular, increased physical activity are advocated for the reduction of risk factors for chronic diseases. Moreover, as part of the Third Report of the National Cholesterol Education Panel (NCEP) Adult Treatment Panel (ATP) III guidelines for decreasing LDL-cholesterol, a risk factor for heart disease, there is a lifestyle component emphasizing diet, weight management, and increased physical activity (5).

Significant studies are available to support the use of lifestyle modification for chronic diseases, and in some cases, better or equivalent results to pharmaceutical therapy are obtained. Three clinical trials have demonstrated that compared with standard of care, lifestyle intervention (diet and exercise or diet alone) reduced progression to diabetes in prediabetic individuals by approximately 40 to 58% (6). Furthermore, the Diabetes Prevention Program analyzed the cost benefit of the lifestyle program to be $15,700 per case of diabetes prevented. Lindstrom et al. (7) showed that lifestyle counseling has sustained benefit. Overweight, middle-aged adults with impaired glucose tolerance who were assigned to a median of four years of active lifestyle intervention (including reduced intake of total and saturated fat, increased intake of dietary fiber, and increased physical activity) had reduced incidence of diabetes for the median total follow-up of seven years compared with the control group which received no counseling (incidence of diabetes was 4.3 and 7.4 per 100 person years in the intervention and control groups, respectively).

While the studies suggest that diet and lifestyle modification are powerful tools for clinical intervention, it would seem that perpetuating unhealthy lifestyle trends have contributed substantially to the onslaught of these chronic issues. Indeed, it is apparent that there have been gross changes in lifestyle over the past several decades, including poor nutritional intake, tobacco use, excessive alcohol consumption, and lack of physical activity.

First, let’s discuss the changes in the food supply. On average, it has been estimated that food travels 1500 miles to the plate. We are eating more convenient, processed foods that contain synthetic ingredients and food additives to keep them living longer on the shelf (8). However, the readily-available influx of these items into our daily meals may not be conducive to the maintenance of good health. For example, one of the products of the food industry has been trans fats. These fats are created when unsaturated (liquid) fats are made more solid and shelf-stable through a process known as hydrogenation. Partially hydrogenated oil (and resulting trans fat) is found in dozens of convenient, processed food items, especially dessert and bread mixes, French fries, margarine, cookies, donuts, and frozen meals. Eating these fats can lead to increased risk for heart disease as their consumption has been associated with increasing levels of LDL-cholesterol (harmful) and reducing HDL-cholesterol (protective). As a result, the National Academy of Sciences has reported that there is “no safe amount” of trans fat.

Aside from fat, the increase in the intake of sugar, essentially a 20% rise between 1970 and 2005, or an average daily current consumption of 22 to 30 teaspoons, has paralleled the rising rates of obesity, and consequently, increasing the risk for cardiovascular disease and type 2 diabetes. The heightened mass consumption of sugar in all forms – high-fructose corn syrup, cane sugar, dextrose, and sucrose – has displaced nutrients in the diet, especially plant compounds which have an array of health benefits. Statistics indicate that despite clever marketing plans to encourage fruit and vegetable consumption such as “5 A Day”, the intake of these high-nutrient foods has not changed much in the past 20 years. In fact, the 2005 Dietary Guidelines for Americans revealed the need for a higher fruit and vegetable recommendation – 5 to 13 servings daily compared with the past recommendation of 5 to 9. According to the “America’s Phytonutrient Report”, 8 out of 10 Americans have a “phytonutrient gap”, implying that they are not meeting their daily required intake with a significant percentage of people missing colorful phytonutrients with specific physiological functions: 69% of Americans fall short on green plant compounds, 78% on red, 79% on yellow/orange, 86% on white, and 88% on purple/blue. In addition to these healthful, pigmented phytochemicals, fruits and vegetables are rich sources of nutrients like fiber, folic acid, vitamins (especially A, C, and E), and potassium. Increased intakes of fruits and vegetables have been shown to be correlated with decreasing rates of chronic diseases such as cancer, obesity, metabolic syndrome, and diabetes mellitus.

By focusing on eating whole, unprocessed foods, and aiming for a natural array of colors with each meal, we can hope to help displace the presence of nutrient-poor foods in the diet which have little or no health benefits. In the past decade, clinical studies employing the Mediterranean diet, which contains fresh foods such as fruits, vegetables, legumes, lean meats and fish, and olive oil, have resulted in improvements in endothelial dysfunction, dementia, metabolic syndrome, and cardiovascular disease. Additionally, in his book, The Blue Zones, Dan Buettner indicates that proportionally-greater centenarian populations tend to eat more plant foods than those that are animal in origin. Thus, the inclusion of high-density plant foods in the diet is strongly warranted in the prevention of chronic diseases.

When it comes to good health, eating whole, unprocessed foods has received a considerable amount of attention from health authorities due to the plethora of scientific data available to support it. In conjunction with consideration of the quality of foods, it is also important to evaluate the manner in which meals are eaten. Overeating, stress eating, and emotional eating all have their disadvantages from a health perspective. Experts estimate that 75% of overeating is caused by emotions. Episodes of emotional eating are most often correlated with the consumption of high-fat and/or high-sugar foods including cake, ice cream, chips, and soda (11). Furthermore, individuals who have high cortisol levels or who are predisposed to reacting to stress may be less likely to exhibit restraint in dietary eating behaviors that result from stressful events like emotional eating or overeating (12). Conversely, mindful eating practice and stress reduction may be helpful for minimizing dietary intake or blunting changes in physiological functions. It is interesting to note that children who are overweight/obese take more bites per minute than children who are normal or underweight (13). Additionally, Rosenzweig et al. (14) demonstrated that a mindfulness-based stress reduction 12-week program was effective in establishing improved glycemic control in type 2 diabetics without changing diet or exercise.

Secondly, in addition to dietary changes, physical activity has a well-established impact on health measures. The effects of exercise go beyond weight loss into benefits for metabolic risk factors such as improving insulin resistance, blood pressure, serum triglycerides, and LDL/HDL levels, as well as for cognitive and psychological well-being (15-18). Unfortunately, about 36% of adults do not meet the recommendations for aerobic physical activity based on the 2008 Physical Activity Guidelines for Americans (19) (see Table 1). More time watching television has been correlated with mortality, especially due to cardiovascular causes (20). Television viewing also leads to effects in modifying food intake, including consuming more calories and making poorer food choices (less vegetables and fruit servings). It has been suggested that even if physical activity guidelines are met, it is not beneficial to sit for prolonged periods (21). Interspersing sedentary time watching television, driving, and using the computer with bouts of activity may reduce premature mortality risk, although further studies are required.

Table 1. Physical Activity Recommendations for Adults ages 18-64 (Source: 2008 Physical Activity Guidelines for Americans published by the U.S. Department of Health and Human Services (

  • Adults should do 2 hours and 30 minutes a week of moderate-intensity, or 1 hour and 15 minutes (75 minutes) a week of vigorous-intensity aerobic physical activity, or an equivalent combination of moderate- and vigorous-intensity aerobic physical activity. Aerobic activity should be performed in episodes of at least 10 minutes,      preferably spread throughout the week.
  • Additional health benefits are provided by increasing to 5 hours (300 minutes) a week of moderate-intensity aerobic physical activity, or 2 hours and 30 minutes a week of vigorous-intensity physical activity, or an equivalent combination of both.
  • Adults should also do muscle-strengthening activities that involve all major muscle groups performed on 2 or more days per week.

Finally, stress reduction is an essential component of lifestyle medicine. It has been estimated that stress is the underlying cause of 80% of diseases. Indeed, the level of stress one encounters may change how they eat and whether they exercise. Being properly nourished and physically fit can help blunt the effects of stress on the body and mind. Modalities such as biofeedback and meditation may be potentially helpful in helping individuals to manage stress responses. In a recent study by Jung et al (22), it was demonstrated that individuals who meditated had higher scores for positive affect and lower scores for stress compared with a control group. Furthermore, mindfulness-based stress reduction (a form of meditation) has been shown to help decrease ruminative thinking and anxiety, and increase empathy and self-compassion (23). Thus, by balancing the autonomic nervous system through various techniques, the chances of chronic disease may be significantly reduced.

In conclusion, rates of chronic disease are on the rise, affecting quality of life, national expenditures, and ultimately, life expectancy. Diet and lifestyle modifications have been shown to be an effective means to prevent and treat common chronic diseases. By altering the dietary intake to include more nutrient-dense whole foods, getting regular, moderate-intensity physical activity, and managing stress levels through physical activity, biofeedback, and/or meditation, an individual can positively affect his or her health throughout the lifecycle into the aging years.


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