newoldme wrote: Last year the big Swedish study came out basically saying that LCHF was good sort term for weight loss, seeming to give good labs and help with satiation, etc, but long term caused cholesterol to rise and presumably cardiovascular disease risk. Conventional medicine were like, "ah, ha!" as it seemed to explain the apparent dichotomy between what diets like Atkins showed on short term and what other studies were showing WRT fats.
Here is a summary:
http://www.theatlantic.com/health/archi ... ad/258343/The 25yr Swedish study:
http://www.nutritionj.com/content/11/1/40/abstractOf course, nothing is ever quite so simple and depending on your personal history and risk factors each needs to make their own choice about what is best for them.
I've just followed up the link to the Swedish study and looking at the full text of the paper, it does not exactly say what the link to the summary reports! In fact it does not look at people who swapped from a low fat to a low carb diet. It looks at fat and carb consumption in the whole study population and notes that at first overall fat consumption decreased and carbs increased but later on this was reversed, at the same time cholesterol levels at first decreased and then later increased while BMI continued to increase over the whole study period. The authors point out that the LCHF diet was promoted in recent years and speculate that this caused the increase in fat and decrease in carb consumption and that this is related to the change in cholesterol.
Men and women in northern Sweden decreased their reported fat intake in the first 7 years (1986–1992) of an intervention program. After 2004 fat intake increased sharply for both genders, which coincided with introduction of a positive media support for low carbohydrate-high-fat (LCHF) diet. The decrease and following increase in cholesterol levels occurred simultaneously with the time trends in food selection, whereas a constant increase in BMI remained unaltered.
However, these observations do not necessarily mean that the change in fat/carb ratio is a cause of the cholesterol findings. The authors point out:
Our study design does not allow a causal evaluation of the relationship between the increased fat intake since 2004 and the increased cholesterol values after 2007, although the parallel trends would suggest such a relationship.
There were many other things that changed over the 25 years of the study, including wine intake, a change from potato and crispbread as the principal source of carbs to pasta and rice, and a change in the types of fats consumed.
This survey is not actually looking at the long-term effect of a LCHF diet at all as we have no idea how many people in the survey were actually eating a LCHF diet. It seems more likely that the promotion of the diet has removed the demonisation of fats in the public consciousness but failed to emphasize the need to remove sugar and starch from the diet in parallel with the increase in fat consumption. Eating a high fat diet combined with a high carb diet definitely leads to obesity and high cholesterol!
The paper does not report whether there was a change in the total energy consumed per day over the course of the study. One might assume that if BMI was progressively increasing that total calories were also increasing and it could be that the increase in fat consumption was not balanced by the decrease in carb consumption. As fat is so energy dense, any increase in weight fats needs to be balanced by a 2.5-fold decrease in weight of carbs consumed in order to have the same energy intake. The foods that are worst for our health combine carbs and fats (i.e., cake, chips etc) so whether you are cutting carbs or fats, these foods should still be kept as treats rather than every day foods!
My take on the LCHF diet is that for most of us, a very low carb diet is not necessary but that decreasing carb intake is probably a good thing. A decrease in carb intake of only 50g per day would decrease calorie intake by 200cals which would add up to a significant decrease in energy intake. For some of us, who are sensitive to carbs (i.e., with diabetes/pre-diabetes) a lower carb diet is necessary. I am currently trying to keep my carb intake to around 150g per day which is fairly easy to do and represents about a 50-75g drop in carbs over my former diet.
I think that we should not be so afraid of fats that we seek low-fat diet foods (because these are often sugar-laden), rather we should moderate our consumption of sugars and starches, eat lots more vegetables and not worry too much about fats but also not unnecessarily increase fat consumption.
Lastly, the relevance of the increase in cholesterol may also be open to debate...
