Let me tell you about my low-fat experience from 20 years ago. At the time, I was living in Cleveland, Ohio, and served on the faculty at a large metropolitan university-affiliated hospital, supervising fellows-in-training and developing high-tech cath lab procedures like directional athererectomy and excimer laser coronary angioplasty. (Yes, another life.)
I was concerned about personal heart disease risk, though I knew next to nothing about lipids and coronary risk prediction outside of the little I learned in training and what the drug industry promoted.
I heard Dr. Dean Ornish talk while attending the American College of Cardiology meetings in Atlanta. Dr. Ornish spoke persuasively about the dangers of fat in the diet and how he "reversed" coronary disease using a low-fat, no added oils, no meat, vegetarian diet that included plenty of whole grains. So I thought I'd give it a try.
I eliminated all oils; I removed all meat, eggs, and fish from my diet. I shunned all nuts. I ate only low-fat products like low-fat yogurt and cottage cheese; and focused on vegetables, fruit, and whole grains. Beans and brown or wild rice were a frequent staple. I loved oatmeal cookies--low-fat, of course!
After one year of this low-fat program, I had gained a total of 31 lbs, going from 155 lbs to 186 lbs. I reassessed some basic labs:
I became a diabetic. All through this time, I was also jogging. I ran on the beautiful paths along the Chagrin River in suburban Cleveland for miles north and south. I ran 5 miles per day most days of the week.
It was diabetes that hit me alongside the head: I was eating low-fat meticulously, exercising more than 90% of the population, yet I got fat and diabetic!
I have since changed course in diet. Last time I checked, my lipid values on NO statin agent:
That was my lesson that fat restriction is a destructive, misguided notion. The data since then have confirmed that restricting total fat is unnecessary, even undesirable, when fat calories are replaced by carbohydrate calories.