Strategies for Healthy Weight Loss: From Vitamin C to
the Glycemic Response
Carol S. Johnston, PhD, FACN
Department of Nutrition, Arizona State University, Mesa, Arizona
Key words: weight loss, vitamin C, high-protein diets, vinegar, peanuts
Abstract America is experiencing a major obesity epidemic. The ramifications of this epidemic are immense
since obesity is associated with chronic metabolic abnormalities such as insulin resistance, dyslipidemia, and
heart disease. Reduced physical activity and/or increased energy intakes are important factors in this epidemic.
Additionally, a genetic susceptibility to obesity is associated with gene polymorphisms affecting biochemical
pathways that regulate fat oxidation, energy expenditure, or energy intake. However, these pathways are also
impacted by specific foods and nutrients. Vitamin C status is inversely related to body mass. Individuals with
adequate vitamin C status oxidize 30% more fat during a moderate exercise bout than individuals with low
vitamin C status; thus, vitamin C depleted individuals may be more resistant to fat mass loss. Food choices can
impact post-meal satiety and hunger. High-protein foods promote postprandial thermogenesis and greater satiety
as compared to high-carbohydrate, low-fat foods; thus, diet regimens high in protein foods may improve diet
compliance and diet effectiveness. Vinegar and peanut ingestion can reduce the glycemic effect of a meal, a
phenomenon that has been related to satiety and reduced food consumption. Thus, the effectiveness of regular
exercise and a prudent diet for weight loss may be enhanced by attention to specific diet details.
Key teaching points:
• Gene polymorphisms associated with biochemical pathways that regulate fat oxidation, energy expenditure, or energy intake have
been linked to genetic susceptibility to obesity.
• 30–70% of the variation in body weight and fat mass can be attributed to genetics; environmental conditions, including specific
dietary factors, may play a pronounced role in the expression of these phenotypes.
• Vitamin C status is associated with tissue carnitine concentrations and fat oxidation and may represent a modifiable condition that
would impact fat oxidation thereby affecting body composition and body mass.
• The thermic effect of food, which accounts for ?10% of daily energy expenditure, is related to dietary protein; thus, the greater
calorie-cost of high-protein diets, in association with the increased satiety of these diets, may protect against gradual weight gain.
• The glycemic response to food ingestion has been associated with subsequent hunger; complementary foods, such as vinegar or
peanut products, when added to meals, may attenuate meal-time glycemia promoting satiety and reduced energy intake.
America is experiencing a major epidemic of overweight
and obesity. In 2001–02, 66% of adults were overweight (body
mass index [BMI] ?25) and 31% of adults were obese (BMI
?30) . In comparison, the prevalences of overweight and
obesity respectively were 46% and 15% in 1976–80 and 56%
and 23% in 1988–94 . Excess weight is associated with the
leading causes of death in the U.S.: cardiovascular disease,
cancer, stroke, and type 2 diabetes. In fact, obesity is quickly
gaining on tobacco as the leading cause of preventable death in
the U.S. In 1993, tobacco contributed to 400,000 deaths annu-
ally versus the 300,000 deaths attributed to diet and inactivity
. By the year 2000, the gap had narrowed considerably with
435,000 deaths annually attributed to tobacco and 400,000
deaths attributed to diet and inactivity . As a sign of the
times, Medicare recently announced that it had changed its
Address reprint requests to: Carol S. Johnston, PhD, FACN, Department of Nutrition, Arizona State University East, 7001 E. Williams Field Rd., Mesa, AZ 85212. E-mail:
Presented in part at the 45th Annual Meeting of the American College of Nutrition in Long Beach, California, September 30–October 3, 2004.
Journal of the American College of Nutrition, Vol. 24, No. 3, 158–165 (2005)
Published by the American College of Nutrition
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Received July 27, 2004; revision accepted February 8, 2005.
Strategies for Healthy, Effective Weight Loss
JOURNAL OF THE AMERICAN COLLEGE OF NUTRITION165