by Hannah Sutter
What’s the best way to eat if you want to stay a healthy weight and lower your risk of various chronic disorders? That’s the big question behind the long running diet war between an embattled low-fat establishment and those in my gang – the low carb/high fat rebels.
My lot scored a notable hit last week when a senior American cardiologist had an article published in the BMJ entitled “Low saturated fat diets don’t curb heart disease risk or help you live longer”. The establishment produced what might have been a successful riposte with a study that claimed failing to keep your protein intake pretty low (it’s easy to eat a lot of protein on a high fat diet) was as dangerous as smoking. I’m obviously biased but several experts showed it to be seriously flawed, especially Zoe Harcombe here.
This can all get pretty confusing for civilians who often have to make important life-style decisions based on the way they interpret these skirmishes. That’s why I want to take a close look at the decision by Diabetes UK earlier this year to give £2.5million (the largest research grant ever made by the charity) to fund a 5-year study into the possibility of reversing type 2 diabetes with a Very Low Calorie Diet (VLCD) . A diet based on calorie counting.
Diabetes is the big prize in this diet war. In fact you could say it was what it is all about. Essentially it comes down to this. People with diabetes have too much sugar in their blood. So is the best way to treat it with a diet that raises blood sugar – low fat/high carbs – or one that lowers blood sugar – high fat/low carbs?
VLCD been around for 40 years
I fully acknowledge my bias but it is clear to me that the grant to fund this study reflects the blinkered approach to weight loss and obesity by a continuing focus on calorie counting and physics rather than biochemistry. Let us not forget that this approach to dieting that has been around for 40 years and has major shortcomings and no evidence that it cuts obesity long-term. Those involved running VLCDs have demonstrated an alarming lack of understanding of human biochemistry and the whole project seems driven more commercial interests than patient benefit.
At first sight this new study, headed by Professor Mike Lean of Glasgow University and Professor Roy Taylor of Newcastle University doesn’t look like being about either high carbs or high fat instead it might look as if it involved a third way that they are calling a Very Low Energy Diet (VLED) that cuts the intake of both of them. The big idea is that if a diabetic loses at least 15 kilograms, they can reverse diabetes. This is what the summary provided by Diabetes UK says:
“Substantial weight loss achieved following bariatric surgery can reverse type 2 diabetes in 70-80% of patients. However research has proved that it can also be reversed by a strict energy restricted diet with around 15 kg weight losses” So Diabetes UK’s support seems to be based on the theory that only weight loss is required and providing it is significant – diabetes will be solved. Blimey it does make you ask competency questions.
The study that triggered this grant was small, lasted 8 weeks and was carried out by Prof Roy Taylor a couple of years ago. It involved 11 adults with type 2 diabetes who followed an 800 calorie-a-day diet that came from low-calorie shakes provided by Nestle. Guess what –if you starve people they will lose weight fast. I am not sure you need a study to show that but what you really want is a study that shows what happens after they have been on a starvation diet.
Why was ketosis not considered?
“We believe this shows that Type 2 diabetes is all about energy balance in the body,” explained Professor Taylor, “if you are eating more than you burn, then the excess is stored in the liver and pancreas as fat which can lead to Type 2 diabetes in some people. What we need to examine further is why some people are more susceptible to developing diabetes than others.”
Clearly Prof Taylor did not think that the lack of carbohydrate in the diet was in any way relevant – only weight loss and keeping it off. Even though the low carbs would mean that the patients’ blood sugars were regularised. We know they went into a state known as ketosis when the body switches from burning glucose from carbohydrates to using fat from the diet and from storage for energy.
Some of this gets turned into energy packets called ketones in the liver. It is the state of ketosis that results in fast and substantial weight loss. What is really odd is that at no point did Prof Taylor or Diabetes UK ask whether the critical issue was the low calories or the ketosis or the lack of carbohydrate. This lack of critical thinking may be linked to the fact that weight-loss shakes maker Optifast part funded the original study and may not want people to know that you can get into a state of ketosis with just food from the local store.