The Case for a Low Carbohydrate Diet for PCOS

We are moving through some questions to determine if we should try a Very Low Carbohydrate Ketogenic Diet (VLCKD) to help with PCOS.  If you have not read them, then you should read the previous posts before this one.

In previous posts, we examined the Dietitian’s Association of Australia’s (DAA) press release recommending that ladies with PCOS increase their carbohydrate intake with ‘grainy bread’.  We concluded that the evidence cited by the DAA did not support that recommendation.

The next question we will look at is:

Is there Other Evidence that Supports Lowering Carbohydrate Intake?

Here, with appropriate cautions, we can leverage the work of an expert.  I point you to this post by Franziska Spritzler a dietitian who favours a low-carb approach for PCOS.

To be clear, we should be as sceptical of Franziska as we are of the DAA and need to be of all experts when ‘the experts are dead’.

In summary, she says:

  1. Her opinion is that standard carbohydrate amount, and timing advice for people with diabetes and PCOS is unhelpful.
  2. Women with PCOS are likely to have metabolic problems, type 2 diabetes and cardiovascular disease.
  3. She mentions the VLCKD pilot study that interested us.
  4. She focuses on hyperinsulinemia and insulin resistance (IR) as core problems for PCOS. The previous study and DAA the press release that we examined also noted that.
  5. She puts forward that the usually recommended carbohydrate diets are not helpful for those conditions whereas a low carbohydrate approach is.
  6. A study looking at the best dietary approach (examining six) was inconclusive; however, none of those was a VLCKD.
  7. She is in favour of a very low carb diet to address PCOS.

I don’t feel that it’s enough to simply encourage weight loss without providing guidance on how to do so in a sustainable way that  has been shown to improve IR and insulinemia — i.e., limiting carbs to 50 net grams per day or less.

What is the Common Ground?

But now I recall that the DAA referred paper put forward that saturated fat caused insulin resistance.

So it seems that most dietitians would agree that a diet that addresses hyperinsulinemia and insulin resistance is best for PCOS; however, they differ over whether those conditions cause (or remediate by the removal of) saturated fat or carbohydrates. Also diets for weight loss are recommended.  Now we are getting somewhere! 

The DAA referred paper cites this study to support that saturated fat (expressed here as fat quality) is the villain.  That study concludes:

Most studies (twelve of fifteen) found no effect relating to fat quality on insulin sensitivity. However, multiple study design flaws limit the validity of this conclusion. In contrast, one of the better designed studies found that consumption of a high-saturated-fat diet decreased insulin sensitivity in comparison to a high-monounsaturated-fat diet. We conclude that the role of dietary fat quality on insulin sensitivity in human subjects should be further studied …

It is inconclusive to me from this study that saturated fat causes insulin resistance.  Further, we find this study which found that in laboratory testing, saturated fat did not cause insulin resistance.  It said about that conclusion:

We acknowledge that this does not agree many epidemiological reports supporting the notion that diets high in saturated fats are associated with insulin resistance and an increased prevalence of type 2 diabetes [1].

It appears that saturated fat causing insulin resistance is far from proven.

More Evidence to Lower Carbohydrates for PCOS?

So back to carbohydrate restriction for PCOS and there is this study.

An 8-week low-starch/low-dairy diet resulted in weight loss, improved insulin sensitivity and reduced testosterone in women with PCOS.

I note that this was a low carb diet, but not necessarily low enough to be ketogenic.  It was also not a randomised control trial as there was no control group. Most participants would have been on less than 130 grams of carbohydrates per day. At 79g of fat (19.5g saturated), this is a high fat, high saturated fat diet.

Nonetheless, the results showed improvements in weight, testosterone and insulin sensitivity (insulin resistance) and an improvement in vitamin D levels, blood lipids (triglycerides, VLDL) with no adverse effects to ‘cholesterol’ overall.

Finally, a third study is this study, which might be missed by many because the 15 PCOS participants were in the cohort of sixty people.

Patients with polycystic ovary syndrome lost 14.3%+/-20.3% of TBW (P=.008) … at 24 and 52 weeks, respectively, without adverse effects on serum lipids.

The diet in this study was a ketogenic diet. The results were similar to the last study. They lost weight, reduced fasting insulin and had no adverse effects on their ‘cholesterol’.

I think it is significant enough to comment that anecdotally, women have a hard time losing weight with PCOS yet the experts are unanimous that overweight women with PCOS should lose weight.  These studies all demonstrated weight loss by carbohydrate reduction for women with PCOS was significant and effective.

Decision Time

But at about this time I come back to the point.  Do I cut my carbs or not or do I I wait for the boffins to settle their argument?

Well this is where I invoke another macrofour principle: 

The experts do not care about N=1 but you do!

In case you are not familiar “N=1” is the retort from an expert to refute an anecdote that someone was cured by doing something. You see they need a lot more evidence than one person before they will agree with or recommend it.  You don’t because you care about your N=1. So at this point, it is simple. You are not getting advice because scientists haven’t solved their arguments in time to advise you now.  You can make this decision for yourself- or it may be years for them to settle their argument. 

corn flake box carbohydrate
Cure please, not cereal

Personally, I am uninterested in scientist’s careers, egos and the various other distractions that could come into it like pharmaceutical profits or that someone wants to sell me a box of cereal.  I just want to get well.

If you have followed a low-fat (and particularly a low saturated fat diet) and your PCOS has not improved enough, then you have already tried the low saturated fat advice.  Did it work for you? If not then your N=1 says to favour the low-carb diet.  Alternatively, if you have been on a low-carb diet for a while and have PCOS, then try cutting saturated fat. 

Finally, if you have followed a high carbohydrate and high saturated fat diet you are either going to have to choose or cut both.  Before we move on to the safety of carb reduction, let us see whether we should lean one way or the other.

Low Carb or Cut Saturated Fat?

I think that the reader can conclude that the weight of evidence presented leans towards reducing carbohydrates, not saturated fat as having a positive effect on PCOS. We couldn’t find anything to suggest that increasing carbohydrates would help.

So despite dietitians being discordant, the weight of evidence leans towards carbohydrate restriction for PCOS.

Further, by looking behind the press release, we found that in particular, some women were reducing sugar.  So, to finish off, here is a recent post from Dr Jason Fung about sugar and insulin resistance.  Dr Fung is a Canadian kidney disease specialist. He advocates low-carb and fasting to help fix insulin resistance and to stop you losing your kidneys to diabetes.

While you read, please consider whether the wisdom of the crowds was present when the PCOS ladies in the DAA referred study chose to cut their sugar. I will prime you with the fact that sugar is the same as sucrose and each sucrose molecule breaks down into a molecule each of glucose and fructose.

Next, we will look at the safety of a VLCKD.

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