DIETA BAJA EN CARBOHIDRATOS
Titulo: A Low-Carbohydrate as Compared with a Low-Fat Diet in Severe Obesity Autores: Frederick F. Samaha, M.D., Nayyar Iqbal, M.D., Prakash Seshadri, M.D., Kathryn L. Chicano, C.R.N.P., Denise A. Daily, R.D., Joyce McGrory, C.R.N.P., Terrence Williams, B.S., Monica Williams, B.S., Edward J. Gracely, Ph.D., and Linda Stern, M.D. Publicacion New England Journal of Medicine Sección: Original Articles Referencia: Fecha: 22/05/03 - Volumen: 348 - Número: 21 Comentario:Una muestra depacientes muy obesos con una prevalencia elevada de diabetes y de síndrome metabólico se asignaron aleatoriamente a una dieta baja en grasas o a una dieta baja en carbohidratos. El seguimiento fue de seis meses. El análisis de los datos indicó que los pacientes que recibieron la segunda dieta perdieron más peso (5,8 kg frente a 1,6 kg; p=0.002) y presentaron un mejor perfil metabólico. De todos modos, las diferencias entre grupos fueron modestas en todas las variables.
Titulo: A Randomized Trial of a Low-Carbohydrate Diet for Obesity Autores: Gary D. Foster, Ph.D., Holly R. Wyatt, M.D., James O. Hill, Ph.D., Brian G. McGuckin, Ed.M., Carrie Brill, B.S., B. Selma Mohammed, M.D., Ph.D., Philippe O. Szapary, M.D., Daniel J. Rader, M.D., Joel S. Edman, D.Sc., and Samuel Klein, M.D. Publicacion New England Journal of Medicine Sección: Original Articles Referencia: Fecha: 22/05/03 - Volumen: 348 - Número: 21 Comentario:En este ensayo clínico de un año de seguimiento, 63 hombres y mujeres fueron asignados aleatoriamentea recibir una dieta rica en proteínas, baja en carbohidratos, y rica en grasa o a una dieta convencional rica en carbohidratos y baja en grasas. Los pacientes asignados al primer grupo perdieron más peso durante los seis primeros meses, pero estas diferencias se diluyeron al año de seguimiento. La dieta baja en carbohidratos se asoció con una mejora en algunos factores de riesgo cardiovascular. La adherencia a cualquiera de las dietas fue baja.
Two New Studies Validate the Atkins' Low-Carbohydrate, High-Protein, and High-Saturated Fat Diet
This web site will prove that eating red meat and natural animal fats while restricting carbohydrates is not only healthy but will prevent and cure many diseases.
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Atkins Diet Shows Surprising Results, Researcher Says; One-year Study Shows Diet May Be As Effective And Safe As Conventional Diets
Source: University of Pennsylvania Medical Center, Date: 2003-05-22
Philadelphia., PA -- A 3-center study led by researchers at the Weight and Eating Disorders Program of the University of Pennsylvania School of Medicine reports the results of the first controlled trial of the Atkins Diet. The Atkins Diet limits carbohydrates but permits unrestricted amounts of protein and fat. Compared to a conventional, high- carbohydrate, low-calorie approach, Atkins dieters lost twice as much weight at 3 and 6 months but there was no difference between the groups at 1 year. Despite the lack of differences in weight loss at 1 year, the Atkins dieters had significantly greater increases in good cholesterol (HDL) and greater decreases in triglycerides.
The study, to be published in the May 22 issue of the New England Journal of Medicine, was led by Gary Foster, Ph.D. Associate Professor of Psychiatry and Clinical Director of the Weight and Eating Disorders Program at the University of Pennsylvania. Samuel Klein, MD of Washington University in St. Louis and James Hill, Ph.D. and Holly Wyatt, M.D. of the University of Colorado were the lead investigators at the other centers. The study investigated 63 obese men and women who were 44 years of age and weighed and average of 216 pounds.
All participants met with a registered dietitian at 0, 3, 6 and 12 months. Those in the Atkins group were given a copy of Dr. Atkins New Diet Revolution and asked to follow the diet as described. The conventional diet group was given instructional materials on a 1200-1500 calories/day (women) or 1500-1800 calories /day (men) diet that consisted of 60% carbohydrate 25% fat, and 15% protein based on the USDA Food Guide Pyramid. Atkins participants lost an average of 14.7 pounds compared with 5.8 pounds in the conventional group at 3 months, 15.2 pounds versus 6.9 pounds at 6 months, and 9.5 versus 5.4 pounds at 12 months. At 1 year, Atkins participants had greater increases in HDL cholesterol (18% vs. 3%) and greater reductions in triglycerides (-28% vs. 1%) than did those following a conventional diet. Neither group showed changes in LDL (bad) cholesterol at 1 year .
"Obesity is a national public health problem, and we need to evaluate alternative weight loss approaches aggressively. Widely recommend low carbohydrate approaches may be premature, but our initial findings suggest that such diets may not have the adverse effects that were anticipated” Foster stated. "The real issue is whether low carbohydrate approaches help patients maintain their weight loss better than conventional approaches. It will also be important to determine whether the effects of the diet on cholesterol are the same during weight maintenance as they are they are during weight loss.” Foster also cautioned.
Results of this first, randomized, controlled study of the Atkins diet suggest that low- carbohydrate diets may not be as harmful as anticipated. "Larger and longer studies are needed to assess the long-term safety and efficacy of low carbohydrate approaches in the management of obesity. These preliminary data suggest that weight losses will be comparable to conventional approaches over a 1 year period, but there may be some favorable effects of a low-carbohydrate approach in terms of triglycerides and HDL (good) cholesterol,” Foster said.
This study was funded through grants from the National Institutes of Health (NIH) General Clinical Research Centers at the University of Pennsylvania, Washington University and the University of Colorado. Others who participated in the study at Penn were Brian McGuckin Ed.M, Research Coordinator; Philippe Szapary, MD, Assistant Professor of Medicine, and Daniel Rader, MD, Associate Professor of Medicine.
Similar findings for a low-carbohydrate diet by another group of Penn faculty working at Philadelphia VA Medical Center were also reported in the May 22 issue of the New England Journal of Medicine. In their 6-month study, Frederick Samaha, MD, and colleagues found that a low carbohydrate diet was associated with greater weight losses, reductions in triglycerides and improvements in insulin sensitivity compared to low-calorie, high-carbohydrate diet in 132 patients who were 53 years old and weighed 288 pounds.
Foster and his colleagues at the Washington University and the University of Colorado are currently enrolling participants for a large, NIH-funded, 5-year study of low- and high-carbohydrate diets.
“This larger study of 360 participants will help us more fully assess the benefits and risks of low-carbohydrate diets on bone mass, kidney function, arterial function and exercise tolerance,” Foster said.
This story has been adapted from a news release issued by University Of Pennsylvania Medical Center.
High Saturated Fat, Starch Avoidance Weight Loss Diet Offers Good Preliminary Results
Source: Mayo Clinic, Date: 2003-11-12
ROCHESTER, Minn. -- In the quest for an effective weight loss diet that also is nutritionally complete, researchers in the November issue of Mayo Clinic Proceedings report preliminary weight loss results of a regimen that is similar to the Atkins diet that are encouraging, but merit further, broader study.
Researchers from Cardiology Research at Christiana Care Health Services, Inc., in Newark, Del., report patients on a high saturated fat and avoidance of starch diet similar to the Atkins diet experienced 5 percent weight loss after six weeks without adverse effects. The Atkins diet is noted for its high-fat and carbohydrate restrictions, which have been shown to result in weight loss.
James Hays, M.D., of the Christiana Care Health Services, Inc. the primary investigator, said the study came about after researchers noted that patients with atherosclerosis or diabetes were also experiencing weight loss with a diet they were prescribing for treatment of the chronic disease.
"For the last eight years, we have been concentrating on dietary treatment of the chronic diseases diabetes and atherosclerosis and have ended up prescribing to patients a diet high in saturated fat much like what Dr. Atkins has advocated for weight loss," Dr. Hays says. "A consistent calorie intake is helpful in treatment of diabetes, so we have prescribed a consistent intake of certain fruits and vegetables rather than Dr. Atkins' step-wise approach and this may have resulted in some other differences."
Although further studies remain to be done, it might be possible to find an optimum diet that results in weight loss, promotes longevity and contains a lot of saturated fat, Dr. Hays said. The Atkins diet relies on ketosis, the decrease in appetite related to the caloric intake. However no long-term studies have determined whether there is a risk of cardiovascular disease.
Others who contributed to the study include Angela DiSabatino; Robert Gorman, Ph.D.; Simi Vincent, Ph.D., M.D.; and Michael Stillabower, M.D., all of Christiana Care Health Services.
The observational study looked at 17 men and six women who self-reported food intake and each lost 5 percent of their body weight in six weeks, Dr. Hays said. The diet prescribed for patients by the physicians was to consume one half of all calories as saturated fat, primarily as red meat and cheese. Eggs and other low-fat forms of protein were allowed, regardless of cholesterol content. Fresh fruit and non-starchy vegetables were prescribed in restricted amounts at each meal. Starch was forbidden.
In an editorial in the same issue of Mayo Clinic Proceedings, Gerald Gau, M.D., of Mayo Clinic's Division of Cardiovascular Diseases and Internal Medicine, writes that researchers should keep an open mind about the Atkins diet and continue to study its metabolic effects.
With this published study, Dr. Gau notes that long-term follow-up and larger numbers of patients are needed for more definitive information. Dr. Gau writes that other diets that restrict calories should also be studied for their risks and benefits.
Mayo Clinic Proceedings is a peer-reviewed and indexed general internal medicine journal, published for more than 75 years by Mayo Clinic, with a circulation of 130,000 nationally and internationally.
This story has been adapted from a news release issued by Mayo Clinic.
North American Association for the Study of Obesity Conference Report
Physicians are often asked about the safety and efficacy of low-carbohydrate, high-protein diets. Unfortunately, very few controlled studies have evaluated these popular regimens. These diets, which are often high in fat, raise concerns about their effects on lipid levels. One such diet, the Atkins Diet, restricts carbohydrates and encourages unlimited consumption of protein and fat. Preliminary results were presented from a 3-center (University of Pennsylvania, University of Colorado, Washington University) randomized controlled trial comparing the Atkins Diet with a conventional low-fat, high-carbohydrate plan that restricted daily caloric intake to 1200-1500 kcal for women and 1500-1800 kcal for men. The study included 63 obese (BMI 33.8 ± 3.4 kg/m2) males and females who were randomized to 1 of the 2 diets. Subjects received an initial session with a dietitian to explain the assigned diet program. At 12 weeks, the researchers found that the Atkins group had a lower rate of attrition (12%) compared with that of the conventional program (30%). In addition, subjects in the Atkins group lost significantly more weight (8.5 ± 3.7%) compared with the conventional group (3.7 ± 4.0%). In terms of serum lipids, the Atkins group demonstrated slight increases in total cholesterol (TC; 2.2 ± 16.6%) and low-density lipoprotein (LDL) cholesterol (6.6 ± 20.7%), whereas the conventional group showed significant decreases in these measures (TC -8.2 ± 11.5%; LDL -11.1 ± 19.4%). High-density lipoprotein (HDL) cholesterol significantly increased in the Atkins group (11.5 ± 20.6%) but did not change in the conventional group, whereas triglycerides showed a significant decrease for the Atkins group (-21.7 ± 27.9%) and no change in the conventional group. At 26 weeks, these changes persisted in both groups even though the sample size was smaller. The researchers concluded that the Atkins Diet produced favorable effects on weight, HDL, triglycerides, and retention compared with a conventional low-fat, low-calorie program, whereas the conventional plan was associated with more favorable effects on TC and LDL cholesterol.
A similar randomized-controlled trial from Duke University was also presented at the conference. The researchers in this study also compared the effects of a low-carbohydrate (LC) diet with a low-fat, low-calorie (LF) program. This study included 120 obese (mean BMI 34 kg/m2) males and females, who all received group treatment for their respective diet programs. At 6 months, both groups had similar rates of attrition, but the LC group lost considerably more weight (13.3 ± 4.6%) compared with the LF group (8.6 ± 5.9%). In addition, the LC group lost significantly more fat mass than the LF group (-9.7 kg for the LC group and -6.4 kg for the LF group). Both groups showed decreases in triglycerides, with the LF group also showing a significant decrease in total cholesterol (-13.5 mg/dL). The LC group showed significant increases in HDL and a significant decrease in Chol/HDL ratio. This pattern of results was similar to those of the 3-center study described above. Longer-term studies are needed to more fully evaluate the safety and efficacy of these popular diet approaches.
The 2002 NAASO meeting will occur in San Diego, California, from February 23 as part of the First Annual Nutrition Week Conference.
Reference Books and Online Support Groups:
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Life Without Bread is an important addition to the growing body of literature on the benefits and importance of low-carb diet. Written by Christian Allan, Ph.D., and Wolfgang Lutz, M.D., the book is based on Dr. Lutz's experience using carbohydrate restricted diets with thousands of patients for more than 40 years. It is based on extensive research in the medical and scientific literature and provides ample references. The book presents a unified theory of how high (and even moderate) levels of dietary carbohydrate cause or exacerbate various health problems and how carbohydrate restriction can help people to recover from those problems.
The book Life Without Bread by Christian Allan, Ph.D. and Wolfgang Lutz, M.D. has a chapter on gastrointestinal diseases. Don't be mislead by the title to believe the cure is the simple elimination of bread. Mr. Lutz's older book is out of print but has essentially the same information. It may even contain more detail than his new book above. Fortunately, Chapter VII: Gastro-Intestinal Tract of the older book can be read online.
The Atkins' New Diet Revolution is the best book for an initial dietary change and quick weight loss, reduced blood pressure and reduced cholesterol. Look for the companion book for recipes. It has some very interesting case studies from the doctor's patients. It includes data from past civilizations proving the low-carbohydrate diet is the most healthy. Robert C. Atkins, M.D.
This is Dr. Atkins newest book. The main topics are the cause, prevention and cure for diabetes and heart disease which have become major health concerns in the United States and many other developed countries. Robert C. Atkins, M.D. with Sheila Buff.
This book by Dr. Michael and Dr. Mary Dan Eades has an excellent chapter on "Leaky Gut Syndrome" which describes the cause of bowel diseases and autoimmune diseases.
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