Fruit and vegetables, WHEL study and McDougall

This was mentioned in the comments section of another thread. Needs its own post!

Because Stan (Heretic) visits some pretty weird places on the net, he led me astray to this bizarre commentary from some vegan low fat nut on the WHEL study. McDougall is a Dr no less. Here are some of the things he has to say:

"Breast cancer is a fatal disease and women will do almost anything to live. They will endure poisoning by toxic chemotherapy, burning with radiation, and mutilation from breast-amputating mastectomy; in the hopes of living a few more days. Obviously, if asked to do so, and given proper support from their doctors and dietitians, they would do something as simple, safe, costeffective, and enjoyable as eating oatmeal and bean burritos while avoiding beefsteaks and cheese omelets"

This initial quote from McDougall sums up what I imagine is the mental outlook of the WHEL study intervention group nicely. Women in the aftermath of breast cancer surgery DO want to live. As the dietary intervention tested in the WHEL study failed utterly to make an iota of difference to breast cancer recurrence, what is the explanation for its failure? This is how McDougall sees it:

"Data collected by asking the study participants about what they ate suggested they were eating more fruits and vegetables and less fat after being given instructions dictated by the study guidelines. But people don’t always tell the truth—they often want to please the investigators, so they tell them what they think they want to hear, which in this case was clearly inaccurate"

I'd summarise this as "the patients lied and the patients cheated". Now just try and reconcile statement one with statement two. Women will do anything to survive, statement one. Women will cheat and lie in a study which is trying to save their lives with vegetables, statement two. McDougall's answer as to what actually happened?

Statement one is correct, they cheated and lied. How can he tell?

Easy, next quote:

"Proof that the data collected from asking the women what they ate was inaccurate is shown in table 2. The women eating “a dietary pattern very high in vegetables, fruit, and fiber and low in fat” were reported to have decreased their daily calorie intake by an average of 181 calories (1719 initially, and 1538 six years later), yet they gained weight"

I hate to mention insulin, but ALL fruit and vegetables raise insulin levels. No one looses weight while insulin levels are high. Fruit and vegetables raise insulin. The only way that you can loose weight on a carbohydrate based diet is by caloric restriction to the extent that insulin levels fall between meals. The WHEL study was not a weight loss project, it was a "fruit and vegetables to save your life" project. Lack of weight loss can be taken as the removal of a variable extraneous to the study. It's a marked plus point about this particular study.

The increased weight in the intervention group, to my mind, is the clincher that the patients DID comply. They ate fruit and veggies, raised their insulin and kept any fat they stored post prandially.

I'd just like to point out that anyone on a vegan low fat diet who IS loosing weight is sourcing their calories from the ANIMAL fat on their own butt (this was a USA study, pardon the phraseology). Any health benefits claimed for veganism WITH weight loss has to accept this undeniable fact. Humans carry animal fat on their butt. Wasting muscles will provide animal protein.

I do have to thank Dr McDougall for one pointer.

Long term readers will know that I tend to believe people unless it's patently obvious that they're lying. The WHEL intervention group FAILED to maintain their fat intake reduction, and reported this truthfully. It was always below the non intervention group's fat intake, but it drifted up to 28.9% of 1538kcal, ie about 40g/d. The non intervention group ended up on 32.4% of 1159kcal (50g/d) of fat.

Why is this good? I was worried, at the back of my mind, that there had to be a reason why the death rate was identical in both groups. Given the background of the SAD, any increase of carbohydrate on top of the saturation levels of PUFA and sugar likely to be eaten routinely should have increased the death rate. The answer seems to be that the fat intake drop never really happened, so carbs never really increased and so luckily no one extra died in the intervention group.

This lack of compliance in dietary fat reduction occurred because the elevated insulin was locking energy in to adipose tissue and so energy had be sourced from the diet. That's called hunger. The effect on weight gain was small, in proportion to the small decrease in dietary fat.

The kindest thing I can say about McDougall is that he is a ranting extremist. He is stuck in his vegan rut and doesn't seem to understand how metabolism works.

The weird thing is that I believe he gets results! How come?

A real low fat diet will dump almost all PUFA. A real Food diet will eliminate all sugar. A hypocaloric weight reduction diet will both reduce insulin levels (a growth promoter for breast cancer) and switch metabolism to animal sourced saturated fat, the best source of calories available. Of course ketosis is out of the question, low fat veganism is a very limited approach.

Does McDougall know what he's doing, to get whatever results he does get?

No way.

Peter