**Public Docket #2003N-0338**

**The Priority for Use of the "Prudent Diet" in Weight Management and
Obesity Prevention**

Frank B. Hu, MD, PhD, Associate Professor of Nutrition and Epidemiology

Harvard School of Public Health

Email: Fhu@hsph.harvard.edu

The current dietary strategies for weight control and obesity prevention
have primarily focused on the role of individual macronutrients (e.g.,
fat, carbohydrates, or protein) or individual foods. Although reduction
in percentage of calories from dietary fat intake is commonly
recommended for weight loss, long-term clinical trials have provided no
good evidence that reducing dietary fat per se can lead to weight loss.
^1,2^Small short-term studies have suggested a role of several diets in
weight control, including a low glycemic index (GI) diet, ^3^a high
protein diet, ^4,5^and a diet with high dairy products, ^6^but these
strategies, like the widely recommended low-fat diet, focus too much on
individual nutrients/foods and do not take into considerations of the
complexities of overall eating patterns.

In the past several years, we and others have employed novel statistical
approaches such as factor analysis and cluster analysis to derive
overall dietary patterns in diverse populations and relate these
patterns to obesity and chronic disease outcomes. Using the large
cohorts of Nurses' Health Study and Health Professionals' Follow-up
Study, we have identified two major dietary patterns: the "Prudent
pattern" is characterized by higher intakes of fruits, vegetables,
legumes, whole grains, poultry, and fish, whereas a "Western" pattern
characterized by higher intakes of red and processed meats, sweets and
desserts, potatoes, French fries and refined grains, independent of
lifestyle factors. We have consistently shown that the Prudent diet is
associated with a significantly lower risk of coronary heart disease,
^7,8^type 2 diabetes, ^9^and colorectal cancer, ^10^whereas the Western
diet is associated with a significantly elevated risk of these diseases.

We and other have also shown that the Prudent diet tends to be
associated with lower BMI, whereas the Western diet is associated with
obesity, higher plasma leptin level, a marker of body fat mass, and
C-reactive protein, a marker of systemic inflammation. ^11^ These data
suggest a potential role of substituting Prudent diet components
(fruits, vegetables, whole grains, legumes, fish, and poultry) for
Western diet components (red and processed meats, refined grains,
sweets, potatoes, and French fries) in weight control and obesity
prevention. Such a dietary strategy, using a simple and friendly
food-based dietary counseling plus portion control, should be easier to
be communicated to the public and to be implemented in dietary practice.
However, use of the whole diet approach for weight control and obesity
prevention has never been tested in randomized clinical trials, and this
should be an urgent research priority. If the Prudent diet can be
demonstrated to be effective in weight management, it can have
far-reaching public health implications because such a diet is most
likely to also reduce risk of cardiovascular disease, type 2 diabetes,
and some forms of cancers in the long run. As for evaluation of diets
for weight control in general, such studies should run for at least
one-two years to establish efficacy in weight management.

References:

1\. Pirozzo S, Summerbell C, Cameron C, Glasziou P. Advice on low-fat
diets for obesity (Cochrane Review). In: *The Cochrane Library, Issue
2*. Oxford: Update Software; 2002.

2\. Willett WC. Dietary fat plays a major role in obesity: no. *Obes
Rev*. 2002;3:59-68.

3\. Ludwig DS. The glycemic index: physiological mechanisms relating to
obesity, diabetes, and cardiovascular disease. *Jama*. 2002;287:2414-23.

4\. Skov AR, Toubro S, Ronn B, Holm L, Astrup A. Randomized trial on
protein vs carbohydrate in ad libitum fat reduced diet for the treatment
of obesity. *Int J Obes Relat Metab Disord*. 1999;23:528-36.

5\. Baba NH, Sawaya S, Torbay N, Habbal Z, Azar S, Hashim SA. High
protein vs high carbohydrate hypoenergetic diet for the treatment of
obese hyperinsulinemic subjects. *Int J Obes Relat Metab Disord*.
1999;23:1202-6.

6\. Zemel MB. Regulation of adiposity and obesity risk by dietary
calcium: mechanisms and implications. *J Am Coll Nutr*.
2002;21:146S-151S.

7\. [Hu FB]{.underline}, Rimm EB, Stampfer MJ, Ascherio A, Spiegelman D,
Willett WC. Prospective study of major dietary patterns and risk of
coronary heart disease in men. *Am J Clin Nutr*. 2000;72:912-21.

8\. Fung TT, Willett WC, Stampfer MJ, Manson JE, [Hu FB]{.underline}.
Dietary patterns and risk of coronary heart disease in women. *Arch
Intern Med*. 2001;161:1857-62.

9\. van Dam RM, Rimm EB, Willett WC, Stampfer MJ, [Hu FB]{.underline}.
Dietary patterns and risk for type 2 diabetes mellitus in U.S. men. *Ann
Intern Med*. 2002;136:201-9.

10\. Fung TT, [Hu FB]{.underline}, Giovannucci E, Hunter D, Stamfper MJ,
Colditz GA, Willett WC. Major dietary patterns and the risk of
colorectal cancer in women. *Arch Intern Med*. 2003;163:309-14.

11\. Fung TT, Rimm EB, Spiegelman D, Rifai N, Tofler GH, Willett WC, [Hu
FB]{.underline}. Association between dietary patterns and plasma
biomarkers of obesity and cardiovascular disease risk. *Am J Clin Nutr*.
2001;73:61-7.