I suspect one reason is they've spent their careers telling people to avoid fat and eat carbs.It's almost impossible for most to admit they've been wrong about everything and may have even contributed to the ill health of their patients.
Another reason, as Atkins has pointed out, is economics. The profit margin on grains is enormous, especially compared to meat. Just look at the price per pound of breakfast cereal. You wanna keep the farmers working? Eat grains. Atkins wrote that it's no coincidence that the food pyramid is also illustrative of the way food is produced in this country, with grains being the most abundant (profitable) and fats the least.
I've been on Atkins for 7 years, and to me, there's no other way to eat.
Last week, the core of the Adkins & Perricone (sp?)diets-salmon- was attacked as full of carcinogens if it is farm raised.
True or driven?
I've picked from Adkins and others to come up with a lo-carb, lo fat diet that took 45 lbs off me in 3 months and I've maintained that level for 8 months.The weight loss has allowed me to exercise enough to drop my rest heart rate to safe levels, even tho I'm a smoker.(have to have some vice)
The only advertised lo carb product I use is Mich Ultra because I was getting a 1-2 pound bounce on weekends from my favorite Yuenglings Lagar and Black and Tan. But I found that Mich Ultra and Guinness have about the same effect.