Dodgy D'Anci

Just a few comments after reading through Stan's latest dodgy paper, the one by D'Anci et al in Appetite.

Here are some of my favorite quotes:

"The present study examined how the initial stages of two weight-reducing diets, a low-carbohydrate diet similar to the AtkinsTM diet, and another with macronutrients proportions typically recommended by the American Dietetic Association (ADA), affect cognitive performance"

Okaaaay. A week of zero carbs, a week of under 8g/d and a week of under 16g/day. If anyone has a spare copy of Dr Atkins New Diet Revolution, perhaps they could send it to D'Anci. She might even read it before her next "similar to the AtkinsTM" study. Or maybe not. After all, quoting the AtkinsTM diet is hard for a main stream nutritionist who thinks high fibre, brightly coloured, mostly leaf based vegetables are actually healthy. Especially the number of servings Atkins suggested of this mainstream approved garbage. You don't get many of the AtkinsTM induction veggies on zero carbs per day!

"To mimic this pattern of restriction and reintroduction of dietary carbohydrate, participants followed a 3-week dietary regimen that included a 1-week period that eliminated carbohydrates. We proposed that dietary carbohydrate restriction would impair cognitive performance in the early phases of the diet, and that this impairment would be ameliorated by the reintroduction of carbohydrate"

This is exactly what they found, that the cognitive impairment of zero carbing can be reversed by as little as 8g/d of carbohydrate. Perhaps skipping the zero carb phase would have left the study with absolutely no anti LC data? After all, the ADA dieters had higher confusion scores than the LC group at all time points...

"...weight loss was not significantly different over the 3-week experimental period, weight loss was less than 2 kg in each group (LC diet M = 1.88 kg; ADA diet M = 1.76 kg; n.s.)"

This is impressive. I can't really see how they achieved this. On an intensely ketogenic, carbohydrate restricted diet there was only slightly more weight loss in the LC group than could be achieved by simply following the ADA advice for weight loss. You would have expected the water loss from metabolism of liver glycogen would have accounted for a significantly greater weight loss in the first week in the zero carb group compared to the ADA group. How can this be? Beats me. Maybe the LC group were told to eat enough protein to keep out of ketosis? How can you tell? Nothing in the methods.

And this one, the absolute crowning achievement:

"Hunger ratings did not vary between the two diet conditions"

Sooooo, the AtkinsTM diet is a NON CALORIE RESTRICTED diet which, if actually followed, produces progressive weight loss. The ADA (low calorie macronutrient balanced) dieter's advice re calories is stated in the methods section as:

"Individuals who selected the ADA diet calculated their recommended caloric intake per day based on their current weight"

The closest I could find to what this really means on the ADA website was:

"An individualized reduced calorie diet is the basis of the dietary component of a comprehensive weight management program. Reducing dietary fat and/or carbohydrates is a practical way to create a caloric deficit of 500 – 1000 kcals below estimated energy needs and should result in a weight loss of 1 – 2 lbs per week."

It doesn't actually say anywhere in the paper how much of anything the participants ate! But what ever they ate, they were either HUNGRY on the AtkinsTM like diet or not hungry at all on a caloric deficit of up to 1000kcal on the ADA diet. Smell of fish here?

Another gem from the homilies in the discussion:

"Participants most likely selected into a diet best fit their eating habits, although this was not assessed. If so, the diet conditions may not have been sufficiently different from normal to produce much dysphoria or food preoccupation"

Zero carb is close to the diet of exactly how many Americans?

And finally (got to stop some time!)

"Another common phrase may be an important reminder to these prospective dieters—You Are What you Eat"

Humans are fat and protein, with a little carbohydrate thrown in. Maybe that's what we should eat!

Peter