Every time someone writes "I'm eating a healthy low-fat diet", I cringe. It's presumptuous to assume that, because the fat content is low, the diet is automatically healthy. The media tell us it's healthy. The government tells us it's healthy. "Experts" tell us it's healthy. It must be healthy, right? Um...
See After-eating effects: Carbohydrates vs. fats and Reduced oxidation of dietary fat after a short term high-carbohydrate diet.
The low-fat diet was white bread, potatoes, tuna, chicken, carrots, canned fruit, fruit juices, cola, jam, marmalade, sweets, and sugar cubes.
The higher-fat diet was less of the above, plus a fat spread, which consisted of a mixture of lard, palm oil, olive oil, and corn oil (the ratio of polyunsaturated to saturated fat was 0.5:1).
Please excuse the following "shouting", but some facts need to be shouted from the rooftops:-
1) LDL CHOLESTEROL (LDL-C) DOES NOT CLOG YOUR ARTERIES. LDL-C IS NOT BAD CHOLESTEROL.
2) OXIDISED LDL-C (OX-LDL-C) DOES CLOG YOUR ARTERIES. OX-LDL-C IS BAD CHOLESTEROL.
3) LARGE, FLUFFY (PHENOTYPE A) LDL-C OXIDISES SLOWLY.
4) SMALL, DENSE (PHENOTYPE B) LDL-C OXIDISES RAPIDLY.
5) AS THE PERCENTAGE OF CALORIES FROM FAT DECREASES, YOU GET LESS PHENOTYPE A AND MORE PHENOTYPE B.
If you don't believe me (and why should you?), see A very-low-fat diet is not associated with improved lipoprotein profiles in men with a predominance of large, low-density lipoproteins, with particular reference to the following figure:-
At 50% fat intake, ~15% of the subjects have phenotype B. At 20% fat intake, ~50% of the subjects have phenotype B. At 10% fat intake, over 60% of the subjects have phenotype B. The subjects were all men, but women are no different in this respect.
Warning: The above study and similar studies by Dreon & Krauss have had the methodology tweaked to achieve a desired result. See The Conflation Game.
And now we have Dietary fat intake and subsequent weight change in adults: results from the European Prospective Investigation into Cancer and Nutrition cohorts.
"Results:...The difference in mean annual weight change was 0.90 g/y (95% CI: –0.54, 2.34 g/y) for men and –1.30g/y (95% CI: –3.70, 1.11 g/y) for women per 1 g/d energy-adjusted fat intake (residual method).
Conclusions: We found no significant association between the amount or type of dietary fat and subsequent weight change in this large prospective study. These findings do not support the use of low-fat diets to prevent weight gain."
Note: -1.30g/y means that as dietary fat intake increased, weight decreased.