Addendum to Do all Diets Fail?

By Jason Fung, MD

From several comments to the previous blog post “Do all Diets Fail?”, it seems that some have interpreted this to mean that I do not support any particular diet.  This is despite the fact that I have spent over a year and 60+ blog posts, and 8 hours of YouTube lectures explaining why diets that reduce insulin (particularly a Low Carb, High Fat diet) are an integral part of a weight reducing strategy.  Also despite the fact that I use LCHF in the IDM clinic on literally hundreds of patients with type 2 diabetes.

However, my point is this.  Obesity is a multi-factorial disease, as I previously wrote about.  This means, that there must be multiple targets in the pathway to obesity.  A LCHF diet, for some people will be sufficient for weight loss.  Many do extremely well.  But we cannot ignore those for whom LCHF is not enough.
Let’s take an analogy of heart disease.  Smoking, high blood pressure and family history all contribute to heart disease.  So, simply stopping smoking is important but not the only strategy to use.  We must also treat high blood pressure.  This does not, in any way, mean that stopping smoking is incorrect.  It is only incomplete.

In the same way, obesity has many facets, one of which is the diet.  Treating only the diet is enough for some, but not enough for others.  We cannot pretend that a LCHF will make 100% of people lean again.  Let’s take a thought experiment, as one of my heroes Gary Taubes is fond of doing.

Suppose, I give you prednisone, the synthetic form of cortisol.  It causes obesity.  As you get fatter and fatter, I, as your physician advise you to go on a LCHF diet.  Will it work?  Of course not.  Your diet was not the problem.  Your problem was the excess cortisol I prescribed to you.  The answer, of course is simple.  Reduce the cortisol.  You must treat the underlying cause of the obesity.  You must understand the aetiology of obesity.  Diet, in this case, is not enough.

In the same way, suppose your problem with obesity is the time dependent development of insulin resistance over two decades.  That insulin resistance is the major pathway by which your insulin stays elevated.  Now, I tell you to watch your diet.  Will it work?  Not likely.  You have addressed the insulinogenic diet, but not the insulin resistance.  Sure, changing you diet will lead to a lowered insulin resistance in 5 years, but that’s not good enough.  (If it took 20 years to develop, doing the reverse will similarly require that amount of time).

Suppose your problem with obesity is due to excessive cortisol due to stress and sleep deprivation.  Or chronic pain from fibromyalgia.  Will a prudent diet help?  A little bit.  A good diet is not going to reduce your cortisol.  If cortisol is the main pathway, that is what needs to be addressed.  I have, in fact, patients in the Intensive Dietary Management Program who I cannot help because their problem is caused by, say anti-psychotic medication that stimulates insulin.  Or fibromyalgia that stimulates cortisol.  Unless I can deal with their underlying cause of obesity, I cannot treat it.  But I certainly can understand it.

So, with regards to diet, refined carbohydrates stimulate insulin the most, and dietary fat the least.  So the most logical dietary treatment is Low Carb, High Fat.  Yes, I am still a firm believer in that.  But sometimes, we need to move past that.

By The Fasting Method

For many health reasons, losing weight is important. It can improve your blood sugars, blood pressure and metabolic health, lowering your risk of heart disease, stroke and cancer. But it’s not easy. That’s where we can help.

Jason Fung, MD

By Jason Fung, MD

Jason Fung, M.D., is a Toronto-based nephrologist (kidney specialist) and a world leading expert in intermittent fasting and low-carb diets.

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