Your Weight: Getting to the Heart of the Matter

by Dagmar Gross

Believe it or not, if you’re carrying 10 extra pounds, you can expect to lose 12 months off your life. The Heart and Stroke Foundation of Ontario has published a pamphlet called the Women’s Heart Health Challenge which indicates that 10 extra pounds may be more hazardous to your cardiovascular health than having diabetes or living with a smoker (smoking can take 60 months off of your life, however). But what is a person’s ideal body weight? Can losing 10 pounds really make a difference? Are there any dangers to "yo-yo" dieting? And how do you keep off the weight once you’ve lost it?

Many of us refer to height-weight charts (which are often out-dated) or compare ourselves to someone whose figure we envy to determine how much we should weigh. But what is considered a healthy body weight? The majority of research studies in medical journals refer to the body mass index, or BMI, which is calculated by dividing a person’s weight (in kilograms) by the square of their height (in metres). A BMI of 20-24 kg/m2 is considered "acceptable", whereas a BMI equal to or greater than 27 kg/m2 is associated with increasing health risks. A BMI that falls between 24 and 27 kg/m2 is either acceptable or has moderate health risks, depending on the study ^{1,2, 3}

Being overweight (BMI over 27) increases the risk of developing any number of serious disorders, including hypertension, cardiovascular disease, diabetes and osteoarthritis ^2,4,5. The good news is by simply losing ten pounds, or 10% of your body weight, a person can significantly reduce the risks. Both short term and long term studies indicate that weight loss lowers blood pressure ^{4, 6, 7}, increases "good" cholesterol (HDL) and may lower "bad" cholesterol (LDL) ^{4, 8, 9}, diminishes abnormalities in heart structure that are associated with obesity 10 , and reduces the odds of getting diabetes and hypertension to the same levels as those of normal weight women ². Weight reduction has also been shown to improve menstrual regularity and fertility ¹¹.

The best way to lose excess weight is through diet and exercise. This combination provides superior results that are maintained at least three years after the weight loss ^12,13,14. In comparison, people who use diet only tend to gain back all of the weight they lost, plus more, within two years ^13,14.

Gaining back the weight you’ve lost will, for the most part, negate any of the benefits or reduced health risks you experienced with the weight loss ^4,5,8. However, the phenomenon of weight cycling, or repeated weight loss and gain, does not appear to have many inherent risks on its own, as shown by several studies that are either inconclusive or have severe limitations ^3,15,16. Also, weight cycling does not seem to affect percentage or distribution of body fat ³. However, premenopausal women who frequently gain and lose weight may have a lower bone mineral density ¹⁷, which could influence the risk of osteoporosis later in life.

It is important for us, especially as women, to keep some perspective on the whole issue of weight and determine what is healthiest for each of us. In fact, one out of every three women with a healthy body weight (BMI between 20 and 24) is trying to lose weight 1. So before embarking on any weight loss program, seek the advice of your physician and calculate your own BMI. This will give you a good idea of how much weight, if any, you really need to lose.

References:

1. Green, K.L., et al. Weight dissatisfaction and weight loss attempts among Canadian adults. Canadian Heart Health Surveys Research Group. J Cdn Med Assoc 157:S17, 1997

2. French, S.A., et al. Weight loss maintenance in young adulthood: prevalence and correlations with health behavior and disease in a population-based sample of women aged 55-69 years. Int J Obes Relat Metab Disord 20:303, 1996

3. National Task Force on the Prevention and Treatment of Obesity. Weight cycling. J Am Med Assoc 272:1196, 1994

4. Pi-Sunyer, F.X. A review of long-term studies evaluating the efficacy of weight loss in ameliorating disorders associated with obesity. Clin Therapeutics 18:1006, 1996

5. Williamson, D.F. Intentional weight loss: patterns in the general population and its association with morbidity and mortality. Int J Obes Relat Metab Disord 21:S14, 1997

6. The Trials of Hypertension Prevention Collaborative Research Group. Effects of weight loss and sodium reduction intervention on blood pressure and hypertension incidence in overweight people with high-normal blood pressure. The Trials of Hypertension Prevention, phase II. Arch Intern Med 157:657, 1997

7. Gordon, N.F., et al. Comparison of single versus multiple lifestyle interventions: are the antihypertensive effects of exercise training and diet-induced weight loss additive? Am J Cardiol 79:763, 1997

8. Van Gaal, L.F., et al. The beneficial effects of modest weight loss on cardiovascular risk factors. Int J Obes Relat Metab Disord 21:S5, 1997

9. Nicklas, BJ., et al. Effects of an American Heart Association diet and weight loss on lipoprotein lipids in obese, postmenopausal women. Am J Clin Nutr. 66:853, 1997

10. Karason, K., et al. Effects of obesity and weight loss on left ventricular mass and relative wall thickness: survey and intervention study. Brit Med J 315:912, 1997

11. Hollmann, M., et al. Effects of weight loss on the hormonal profile in obese, infertile women. Hum Reprod 11:1884, 1996

12. Miller, W.C., et al. A meta-analysis of the past 25 years of weight loss research using diet, exercise or diet plus exercise intervention. Int J Obes Relat Metab Disord 21:941, 1997

13. Grodstein, F., et al. Three-year follow-up of participants in a commercial weight loss program. Can you keep it off? Arch Intern Med 156:1302, 1996

14. Skender, M.L., et al. Comparison of 2-year weight loss trends in behavioural treatments of obesity: diet, exercise, and combination interventions. J Am Diet Assoc 96:342, 1996

15. Muls, E., et al. Is weight cycling detrimental to health? A review of the literature in humans. Int J Obes Relat Metab Disord 19:S46, 1995

16. Itoh, T., et al. Effects of weight cycling on coronary risk factors. J Epidemiol 6:55, 1996

17. Fogelholm, M., et al. Association between weight cycling history and bone mineral density in premenopausal women. Osteoporos Int 7:354, 1997

Dagmar Gross, M.Sc., is president of MedSci Communications & Consulting Co., which specializes in technical writing and meeting planning services for the medical, scientific, and health communities. Ms. Gross may be contacted at: 2 Bloor St. West, Suite #100-385, Toronto, ON, M4W 3E2, Tel: 416-968-9414, Fax: 416-968-9417, E-mail: [email protected]

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