Bottom Line on Satiety and the Atkins Diet

A ketogenic diet such as advocated by Atkins and others may very well prove to provide a greater satiety level on fewer calories than a typical American diet. The lower energy density of the diet coupled with its higher protein intake and dramatic reduction in the variety of foods allowed probably account for its effectiveness in terms of weight loss. However, given the long list of proven and likely adverse effects from following a ketogenic diet for a prolonged period of time it seems inappropriate for responsible health professionals to promote Atkins-style ketogenic diets for weight loss.

Appendix – Ongoing Discussion of Studies and Topics That Use the Atkins Diet Approach

 

Does New Study Vindicate Atkins?
A recent study of about 300 middle-aged obese men, average age 51 and average BMI 31, purported to examine the impact of a “Low-Carbohydrate” (LC) Diet, a “Low-Fat” (LF) Diet, and a “Mediterranean” (Med.) Diet on weight loss and cardiovascular disease (CVD) risk factors. This study received widespread media coverage in July 2008 with some reports suggesting the results of this study vindicated the claims of the late Dr. Robert Atkins. Dr Atkins’ books claimed that a low-carbohydrate, high-fat diet with lots of saturated fat and cholesterol-rich animal products not only promoted weight loss but also was heart healthy. However, a closer look at the study’s design and results suggests it does little to vindicate Atkins claim that his diet was heart healthy.


This new study was conducted in Israel and was funded by the Atkins Foundation. However, the researchers stated that the foundation did not influence their study. This is rather a curious claim since the late Dr. Atkins stated in his many books that a diet high in meat, eggs, cheese, butter and other animal fats does not adversely impact blood lipids and was heart healthy as long as carbohydrate intake was severely restricted. In this study the subjects assigned to the LC Diet were counseled to “…choose vegetarian sources of fat and protein…” and yet also claimed the LC Diet “…was based on the Atkins diet.” Anyone familiar with the Atkins diet knows he did not primarily advocate tofu and vegetable oils in place of carbohydrate-rich foods so surely the researchers knew this as well. So why did they have their subjects following a diet they claimed was based on the Atkins diet avoid lots of meat, cheese, and butter? Perhaps they realized such a diet would raise total and LDL-cholesterol levels and promote heart disease.


While the authors of this study claimed no conflicts of interest it should be noted that Dr. Stampher works with Dr. Willett at Harvard Medical School and the Med. Diet used in the study was based on Willett’s version of a Mediterranean Diet.


Here are the interesting points that we believe make this study’s results deceiving:


• The Med. Diet and the LF Diet had the same amount of saturated fat and cholesterol
but the Med. Diet had about 50% more fiber. Willett is a big fan of olive oil but it is fiber-free and had the LF Diet they used been similar to that advocated by Pritikin, Ornish, and others, the LF diet surely would have had more rather than considerably less fiber than the subject’s own basal diets.

 

• Indeed, the LF Diet used in this study had the same % fat and saturated fat as the subjects’ original diet. According to the authors, the Med. Diet had only 3% more fat and the Atkins-style LC Diet only 9% more calories from fat than the LF Diet did.

 

• Weight loss and weight maintenance were somewhat better on the LC and Med. Diets than the LF Diet with subjects after 2 years losing 10.3, 9.7. and 6.4 pounds respectively on the 3 diets. The dietary data reported that calorie intake was reduced by 200 calories a day more on the LF diet than on the Med. Diet, which makes little sense given the somewhat greater weight loss and no greater activity level in those on the Med. versus the LF diet.

 

The HDL levels rose roughly in proportion to the loss of weight and triglyceride levels fell more in those who lost more weight, which is no surprise. One might look at the results of this study and conclude that a LC Diet and Med. Diet are better for weight loss than a LF Diet. However, this is a bit of a stretch because research has shown that the relative impact of modest changes in the ratio of fat to protein to carbohydrate in the diet have little or no impact on ad libitum energy intake compared to that of calorie density. Was the calorie density of the experimental diets in this study controlled? If not, it is quite possible the difference in weight loss on the 3 diets could be explained by differences in calorie density.


Bottom Line:
This study’s results on CVD risk factors are not all that surprising given the questionable design of the study. The fact is all 3 experimental diets failed to lower Total and LDL-cholesterol levels, which is in marked contrast to the many studies of very-low-fat, near vegetarian diets. Furthermore, the lack of attention to important dietary variables like calorie density and percent of calories consumed as beverages which do impact calorie intake, is inexcusable in a study today that purports to examine the impact of diet on body weight regulation. Indeed, the results of this study and the media reports that followed will likely further confuse people and sadly some health professionals about the likely impact of healthy low-fat diet based mostly on minimally processed whole grains, fruits and vegetables for aiding weight loss and preventing and even reversing CVD.

 

By James J. Kenney, PhD, RD, FACN


References:
1. N Engl J Med 2008;359:229-41
Read the full article (115 pages) until 12/2010 at http://www.foodandhealth.com/cpecourses/AtkinsNew.doc

 


 

A Strict Mediterranean Diet Can Help Reduce Deaths From Major Chronic Diseases

Adherence to Mediterranean Diet and Health Status: Meta-Analysis
Sticking to a full Mediterranean diet provides substantial protection against major chronic diseases including heart disease, cancer and Parkinson's and Alzheimer's disease, according to a study published on bmj.com today.


A 'score' based on adherence to the Mediterranean diet could be used as an effective preventive tool for reducing the risk of premature death in the general population, say the authors.


The Mediterranean diet from populations bordering the Mediterranean Sea has a reputation for being a model of healthy eating and contributing to better health and quality of life. It is rich in olive oil, grains, fruits, nuts, vegetables, and fish, but low in meat, dairy products and alcohol.


Previous research on the Mediterranean diet suggests that it has a protective role in cardiovascular disease and cancer, but no study has reviewed all the available data for a possible association between sticking to the Mediterranean diet, premature death, and the occurrence of chronic diseases in the general population.


A team of researchers from the University of Florence assessed 12 international studies, which collectively included more than 1.5 million participants whose dietary habits and health were tracked for follow-up periods ranging from three to 18 years.


All the studies examined the concept of using a numerical score to estimate how much people stuck to the diet, called an 'adherence score'.


The researchers found that people who stuck strictly to a Mediterranean diet had significant improvements in their health, including a 9% drop in overall mortality, a 9% drop in mortality from cardiovascular disease, a 13% reduction in incidence of Parkinson and Alzheimer's disease, and a 6% reduction in cancer.


The researchers suggest that keeping an 'adherence score' based on "a theoretically defined Mediterranean diet could be an effective preventive tool for reducing the risk of mortality and morbidity in the general population."


The results of this study have important implications for public health, particularly for reducing the risk of premature death in the general population, conclude the authors.


The findings confirm the current guidelines and recommendations from all major scientific institutions that encourage a Mediterranean-like dietary pattern for the prevention of major chronic diseases.


BMJ-British Medical Journal