Fashionable Fitness Foods and Futility
It's been said "diets don't work". Most dieters lose weight to start, but gain it back and wind up as heavy or heavier than when they started, even while maintaining the diet all along. Like fads, fashions and manias new diets and diet books come and go. Thousands have been written by crackpots, celebrities, self-styled wellness gurus, and medical Ph.D.s alike.
If diets don't work, does "eating healthy" work? If you've heard it once you've heard it a thousand times: eat right and live longer. Everybody seems to assume diets work in that case.
What happened when eating healthy was put to the test? Not fad diets written by crackpots, celebrities, or self-styled wellness gurus, but the lifestyle diets recommended by major medical institutions and government guidelines on healthy eating. You know, low fat, high fiber, lots of fruits and vegetables, no added sugar and all that. Tried not on rats or mice in labs, but on real people in the real world eating real food.
Enter the Women's Health Initiative (WHI) Dietary Modification Trial. 48,835 postmenopausal women were assigned randomly to a low-fat, high fiber diet or left on their regular diet. By study's end the dieters were eating 29% fat, compared to the control group's 37% fat, and ate about 25% more fruits and vegetables, grains and fiber than the group on your typical American diet.
After eight years they discovered... drumroll... There was no difference in the incidence of breast cancer, colon cancer, heart attacks or strokes among those eating "healthy" and those eating whatever they wanted.
The researchers concluded: "A dietary intervention that reduced total fat intake and increased intakes of vegetables, fruits, and grains did not significantly reduce the risk of CHD (coronary heart disease), stroke, or CVD (cardio-vascular disease) in post-menopausal women." Not only that, but among the women who had heart disease symptoms at the beginning of the study, the low-fat diet slightly increased their risks for heart disease. Lastly they wrote: "A low-fat eating pattern does not result in weight gain in postmenopausal women."
They didn't claim the low-fat diet made you thinner, rather it didn't make you fatter. Subjects lost some weight at the start, but regained it before the end, despite eating 361 fewer calories a day than at the start of the study. At the end, weight change differences between the two groups was less than two pounds.
We next look at the Framingham Heart Study, set up by Harvard University Medical School in Framingham, Massachusetts in 1948, which continues to this day. It's the main study which gave us the all so familiar, widely reported dietary risk factors.
First, the researchers measured cholesterol intake and compared it with blood cholesterol. While subjects ate varying amounts of cholesterol, there was little or no difference in the levels of blood cholesterol. (Interestingly, women eating the least cholesterol had the highest blood cholesterol.)
Next, they studied saturated fat consumption, yet again could find no relation. Nor was there a relation when they studied intake of total calories. They explored the possibility something was masking the dietary effects, but no other factor made any difference. After twenty-two years of research, they concluded: "There is, in short, no suggestion of any relation between diet and the subsequent development of CHD in the study group."
The Journal of the American Medical Association (JAMA) carried a follow-up report 27 years later showing dietary saturated fat reduced the number of strokes. Tending to affect older men, they wondered if a fatty diet was causing subjects to die of CHD before they had a stroke. The researchers discount this, saying: "This hypothesis, however, depends on the presence of a strong direct association of fat intake with coronary heart disease. Since we found no such association, competing mortality from coronary heart disease is very unlikely to explain our results."
In other words, after nearly 50 years of research, they haven't shown a connection between diet and heart disease.
The Multiple Risk Factor Intervention Trial (known as MR. FIT) was one of the largest medical studies ever performed. Involving 28 medical centers and 250 researchers costing $115 million, they studied 361,662 men at very high risk to hopefully get a significant result. They cut cholesterol consumption by 42%, saturated fat consumption by 28% and total calories by 21%.
All for naught. Blood cholesterol levels fell slightly and coronary heart disease was unaffected. Calling the results "disappointing" the originators concluded: "The overall results do not show a beneficial effect on Coronary Heart Disease or total mortality from this multifactor intervention." The multi-factor intervention being "eating healthy".
The Tecumseh Study tried to correlate the amount of fats eaten with blood cholesterol levels measured the following day — yet found none. Rather it was subjects eating the least cholesterol who had the highest levels of blood cholesterol. Also, blood cholesterol levels were unrelated to whether the dietary fats were saturated or unsaturated.
The World Health Organization's European Coronary Prevention Study results were called "depressing" as no correlation between fats and heart disease could be found. Cutting saturated fats down to only 8% of daily calories, they found in the UK section there were more deaths in the dieting group than in the control group.
A five year Finnish trial published in 1975 appeared to support the 'healthy' dietary fat recommendations. Cholesterol levels were lowered, and the study was hailed as a success. However, the results of a 10-year follow-up showed those people continuing to follow the cholesterol-lowering diet were two times as likely to die of heart disease as those who didn't.
FIT Heart (Family-Based Intervention Trial to Improve Heart Health) 501 healthy adults, family members of patients hospitalized for an acute cardiovascular event, were randomly asigned to a control group or an intervention health education group. This healthy lifestyle education focused on avoiding foods with saturated fat, cholesterol, partially hydrogenated fats, transfats and refined sugars; and recommended five daily servings of fruits and vegetables and foods high in fiber. The intervention group was encouraged to engage in 30-60 minutes of moderate physical activity a day and smokers to stop smoking.
At the one-year follow-up, the investigators found no difference in the cholesterol levels between the intense behavioral intervention and control groups. The FIT-Heart study's lead author, Lori Mosca, M.D., MPH, Ph.D., acknowledged the failure of lifestyle modifications in reducing their primary endpoints, the usual reported cardiac "risk factors".
Have they even really figured out the right risk factors? What about the great modern boogyman, cholesterol?
The MONICA Study, sponsored by the World Health Organization, analyzed the relation between cardiovascular mortality and blood cholesterol in 27 countries. The results show countries like Japan and China have low mortality and low cholesterol levels, and countries like Finland have high mortality and high cholesterol levels. Yet countries like France, Germany, Switzerland, and Luxembourg have a low mortality rate and high blood cholesterol.
The study revealed great differences in mortality between different regions with the same cholesterol levels. Residents of Corfu have a 5 times greater mortality than residents of Crete, despite identical diets and identical cholesterol levels. Residents of the North Karelia regions of Finland have mortality rate of nearly
HF-ACTION (Heart Failure: a Controlled Trial Investigating Outcomes of Exercise Training). Participants were randomized to an exercise group or a control group left to their own devices. The first group attended 36 supervised exercise training sessions, as well as home-based exercise. Later transitioning to home exercise only with refresher exercise routines every three months.
After two and a half years, there was no difference between the intense exercisers and the control group in all-cause mortality or hospitalizations. The study's lead investigator, Christopher M. O'Connor, M.D., admitted this trial failed to show a benefit in meeting its primary endpoint of all-cause mortality or hospitalizations. A secondary analysis reported there was still no difference in all-cause mortality rates between the groups after three years.
This all seems somewhat paradoxical, none of the "healthy" diets recommended seem to work. Not for your average person nor for the high risk subjects with the most dramatic diet changes. But there's more. The overweight outlive people at the supposed ideal weight.
Consider the INVEST trial, a randomized international study of 22,000 patients with hypertension and coronary artery disease age 50 and over. The patients got cardiovascular workups including BMI (body mass index) calculations, and were followed for an average of 2.7 years.
The INVEST findings: Compared to normal weight patients, thin patients had 74% higher risk of both death and having a heart attack or stroke, and overweight patients had 29% lower risk. The obese had the lowest risks of all, nearly half that of normal weight patients.
Adjusted for health risk factors and diseases, such as kidney disease and congestive heart failure, researchers found being overweight and obese was associated with lower risks, 1/3 to 1/4 that of patients of normal weight. Being thin had a 52% higher risk; advancing age a 63% higher risk; smoking a 40% higher risk. They concluded: "Our study is in agreement with previous studies that observed an obesity paradox in patients with previous cardiovascular disease... Our results suggest a protective effect of obesity in [these] patients."
UCLA researchers analyzed the Acute Decompensated Heart Failure National Registry and the more than 108,000 cases of acute heart failure in hospitals nationwide from October 2001 through December 2004. Adjusting for every contributing factor, they found for every 5 unit increase in BMI (body mass index) the risk of dying dropped by 10 percent.
Among men with symptoms of heart disease, the overweight tend to live longer than their normal-weight counterparts. Researchers found among nearly 7,000 male military veterans assessed for symptoms of heart disease, the overweight were less likely to die over the next seven and a half years compared with normal-weight men.
The National Institutes of Health conducted an expert review showing weight gain with age for both men and women reduces death rates. At the same time dieting, weight loss or fluctuating weights (yo-yoing), increases the risk of death, cardiovascular diseases, type 2 diabetes and cancers.
All this seems completely contrary to the popular wisdom and is often called the "obesity paradox." Study after study showing fat people living longer and no connection between fat laden diets and poor health nor between so-called "healthy diets" and better health. Of course, this is only a paradox if being thin really should be healthier than being fat, especially as we age. The facts are as we are getting heavier, heart disease death rates have been dropping for more than five decades — 22% between 1993 and 2003 alone.
Ironically, many of the studies cited above were done to see just how much benefit there is from eating healthy and thereby establish guidelines. Yet they could find no clear benefits by the dietary changes. You have to wonder why do they tell us a low-fat, low calorie, high-fiber diet with more fruits and vegetables will help us live longer, but when they've actually tried these diets they make no difference?
Interesting how when the "healthy" diets fail to work as expected, the researches call it "depressing" or "disappointing". They seem to prefer it if we were harming ourselves with the foods we love to eat. Personally, I find the results the very opposite of bad news. It would appear our good old regular diet full of tasty fat may not be killing us after all. You can have your cake and eat it, too.
Which means the paradox may not be in the unexpected results, but in the continuing expectations despite the failures. If you follow the evidence and conclude the hypothesis is wrong, there is no paradox at all.
Eat healthy and live longer? I guess that really depends on what eating healthy really is.
© Terry Colon, 2011
Additional Food for Thought
The hypothesis favoring polyunsaturated fats having a protective or preventative effect on CHD fares no better when studied. In Israel, where polyunsaturated fats consumption was nearly twice that of most Western countries, there was a higher incidence of CHD. In a New South Wales trial, those on high polyunsaturated diets did significantly worse than those on a free diet. None of these results are the exception, most trials that increased the ratio of polyunsaturated fats garnered similar results.
Furthermore, as early as 1971 excess cancer deaths have been reported in trials using diets high in polyunsaturated fats. Such fats are also blamed for a doubling in the incidence of gallstones in the general public.
Growing Up Today Study (GUTS) Led by Allison Field at Brigham and Women's Hospital and Harvard Medical School examined the health and lifestyles of more than 16,000 children, ages 9 to 14. The study found, regardless of overweight status, dieting children gained more weight compared to children who didn't.
This confirms another study by the same researchers finding frequently dieting girls were nearly 4 BMI points higher versus never or rarely dieting kids. Even after accounting for other factors, including physical activity, television watching, etc., the researchers couldn't find a connection between so-called junk food consumption and weight among these kids after 3 years. The bottom line, fat kids weren't eating more sweets than thin ones.
Clinical Psychology Review David Garner, Ph.D. and Susan Wooley, Ph.D., reviewed 500 studies on weight in Clinical Psychology Review and concluded: "Multiple researchers, using a variety of methodologies, have failed to find any meaningful or replicable differences in the caloric intake or eating patterns of the obese compared to the non-obese to explain obesity."