Unfortunately, an increasing number of people are overweight. This contributes to hypertension and diabetes which are the two major causes of chronic kidney disease. Being overweight is a component of the "metabolic syndrome," which includes high levels of cholesterol, triglycerides, and increased uric acid. These factors predispose to cardiovascular disease (heart attack, stroke, dementia, peripheral vascular disease, etc.) Finally, being overweight places an extra burden on the hips, knees and ankles and accelerates osteoarthritis. Therefore, a successful plan to reduce weight is an important component of a healthy lifestyle. However, a sustained reduction in body weight is
hard to achieve.
There are two general approaches to weight loss. The first is appropriate only to patients who are very severely overweight and who have failed several sincere efforts to reduce weight by diet. This is the surgical approach which is now recognized to be the most effective way of reducing body weight long term. Obviously, this is invasive, expensive and not a first-choice option. This is not discussed further in this handout.
The second approach is lifestyle modification. To be successful, weight reduction requires the following components, all of which should be carefully thought through in advance and an appropriate program initiated:
1. A change in eating habits. This requires a commitment to eat more freshly-prepared foods in the home, to avoid fast foods and to choose foods selectively when it is necessary to eat out of the home.
2. A commitment from your spouse, family and friends to assist in your weight reduction program. Only by having this encouragement is a sustained change in eating habits likely to be achieved. A weight reduction program requires some modification in the behavior of the rest of the family to give you the support that you need to be successful.
3. Regular aerobic exercise. This has four important effects. First, exercising reduces appetite. Secondly, exercise increases calorie expenditure (albeit modestly) and therefore assists the weight loss program. For example, the exercise program that is recommended below will expend sufficient calories to reduce weight by 2 pounds per month. Although, this is only a modest change, if maintained over a year it translates into a very worthwhile
20-25 pounds in weight loss. Third, exercising aids cardiovascular health and leads to a reduction in blood pressure. Fourth, exercise improves well-being. An appropriate goal is 30 minutes of aerobic exercise 7 days per week. The exercise must be within your physical and cardiovascular capabilities. This might take the form ofjogging or aerobic exercise in a gymnasium for those able to manage such a program. For others, it could be walking or playing a sport. Regardless, the important components are that it be aerobic (i.e. increases the heart rate and should lead to perspiration), of reasonable duration, and be incorporated into daily life.
4. Set a goal for weight reduction and establish a program to monitor progress. You should work with your physician to establish a goal for your body weight. The physician should provide encouragement where weight loss is continuing or help to troubleshoot problems where weight loss is failing. Weigh yourself on the same scale each week; it is good to combine this with measurements of your home blood pressure. Bring these results to your clinic visits. Select a weight-loss program that can provide additional support. When available, seek help from a nutritionist, or perhaps join a group such as Weight Watchers. These are valuable resources to promote weight reduction.
5. Choose an appropriate and acceptable diet. All diets must reduce your caloric intake if they are to lead to a reduction in body weight. Weight-reducing diets previously were based on low-fat intake. This is logical, since fat contains a lot of calories and was thought to contribute to high levels of cholestero1. Unfortunately, the low-fat diet is difficult to follow, does not reduce cholesterol significantly, does not reduce cardiovascular risk, and is not very effective in weight reduction. A second approach is to restrict your carbohydrate intake. The scientific basis for this is that sugars from the carbohydrates in the food stimulate insulin secretion, which promotes appetite and the laying down of fat. During the first week, a low-carbohydrate diet triggers a significant loss of body salt and fluid. This provides an encouraging initial weight loss, but this loss will be represented as weight gain if the carbohydrate intake of the diet is increased at any time.
A number of recent controlled clinical trials have compared diets based on fat
restriction with diets based on carbohydrate restriction. Carbohydrate restriction is about twice as effective in producing weight loss over 6 to 18 months. Remarkably, despite the higher intake of fat, the low-carbohydrate diets are associated with better control of blood cholesterol and better control of blood sugar than the low-fat diets. Both diets reduce blood pressure in hypertensive subjects. The reduction in blood pressure follows the degree of reduction in weight. Therefore, diets based on low carbohydrate intake are presently preferred for weight reduction and lowering of blood pressure. However, we do not yet have the final piece of evidence that a reduction in weight and cholesterol provided by following a low-carbohydrate diet for many years does translate into the anticipated benefit of a reduction in the development of cardiovascular disease or diabetes mellitus. As is so often the care in medicine, we have to make recommendations based on the best available evidence, but recognize that these may change over time as new clinical research studies are completed and reported in medical literature.
The most well-established low-carbohydrate diet is the Atkins diet. Variations of Atkins diet are the Mediterranean diet, which includes olive oil or nuts and a glass of red wine daily, the South Beach diet, which avoids foods with a high glycemic index and contains a high proportion of vegetables and fruits, and a number of other similar diets. For many, the Atkins diet may be a good way to start dietary planning.
There is no easy way to lose weight. For those of you who are severely overweight, the process of achieving goal body weight will require a sustained effort from you, your family and friends over a prolonged period of months or even years. When you have achieved your goal weight, it is not the end of the process but only the beginning of a lifetime of attention to body weight. Each of us has a strong drive to regain the original body weight after weight reduction. This can only be prevented by prolonged surveillance, a total commitment, and the help of others.
Some books that are written for people without technical knowledge of medicine include the following:
- Casey, Aggie and Benson, H. The Harvard Medical School Guide to Lowering Your Blood Pressure. Publ: McGraw-Hill, 2006.
- Rowan, R. Control High Blood Pressure without Drugs. Publ: Simon & Schuster, 2001.
- Willett, W.C. The Harvard School ofPublic Health Guide: Eat. Drink, and Be Healthy. Publ: Simon and Schuster, 2005.
- Walser, M. Coping with Kidney Disease. Publ: John Wiley, 2004.
For a more detailed account that could be helpful as a reference, you can look over the chapters on Hypertension in:
- Wilcox, C.S. and Tisher, C.C. Handbook of Nephrology and Hypertension, Sixth Edition. Publ: Lippincott, Williams and Wilkins, 2008.
- Wilcox, C.S. Therapy in Nephrology and Hypertension, Third Edition. Publ: Elsevier, 2008.
- Documenta Geigy: Scientific Tables, Seventh edition, Publ: Geigy Pharmaceuticals, 1970, pp 499-515. (This contains the caloric, carbohydrate, salt etc, content of all common foods.)
All of these books are available for loan to patients from our office. Please ask our receptionist and she will loan you a copy for your use at home. Please try to return the books within 2-4 weeks so that they are available for use by other patients.
For those who would like to have a nutritional consultation, you can contact:
Cell phone: (202) 390~8044
To Research for further information, please visit: http://www.cnpp.usda.gov/DGAs2010-policydocument.htm