This study represents one of the very few well-designed diet
studies that attempt to look at weight loss programs in a real world and help
consumers to find a way in a forest of loud marketing materials.
The researchers reviewed four popular diet books that
represent different approaches:
- “Dr. Atkins New Diet Revolution” promoting the lowest
- “Enter the Zone” by Berry Sears being less restrictive for
- The “Eat more, Weight less” plan by Dean Ornish focusing
on fat cuts; and
- “Learn Manual for Weight Management” is a high-carb diet
that essentially follows government health guidelines.
The Stanford University researchers who followed 311
overweight women assigned to different diets performed the study. These women
also attended seminars educating about each diet for eight weeks. Even paid,
they could not follow strict rules of any diet. While the Atkins diet requires
50 gr of daily carbs women ended up taking 150 grams. Followers of the Zone
diet consumed 45% of carbs and 20% of protein, instead of 40% of carbs and 30%
of protein. Women on Dean Ornish low-fat diet ate 30% of fat instead of
requiring 10%. The Learn dieters took 47% of carbs and 20% of saturated fat,
but not 60% of carbs and 10% of fat as prescribed by this diet.
As a result the women in the Zone group lost the least
amount of pounds, -3.5, but none of the diets produced anything dramatic. After
a year of trying to lose even 10 pounds these women still are in the class of
overweight. There was no significant difference in “bad” cholesterol results on
any diet. Long-term effects of diets like high protein and high fat diet
remained unknown. Claims that very low-fat diets reverse heart disease are not
The bottom line is that any strict diet is not good for
health unless under specific medical conditions. The majority of diets are based on
weak scientific evidences, but good marketing strategies.
The main message is: do not count obsessively calories but
just eat smaller portions and only when you are really hungry.