Why using macronutrient percentages is so wrong.

From http://sciencelearn.org.nz/Contexts/Food-Function-and-Structure/Sci-Media/Images/Macronutrient-percentages

1. Deception

Consider Lies, damned lies and statistics, part n+1. Riera-Crichton et al.  

Relative fat intake in %E decreased and obesity increased.

The conclusion:- "Carbohydrates are fattening and fat is slimming." Yeah, right!

Absolute fat intake in grams/kcals increased after healthy eating guidelines (which weren't low-fat guidelines) came out in 1980, according to More Thoughts on Macronutrient Trends.

Gary Taubes & Nina Teicholz use this deliberate misrepresentation of data to create the false narrative that low-fat healthy eating guidelines caused the obesity epidemic in the US. It's a pack of lies.

2. The terms "Low Fat" and "High Fat" are meaningless

Take 55g of fat (500kcals), 125g of protein (500kcals) and 375g of carbohydrate (1,500kcals). It adds up to 2,500kcals, with a percentage C/F/P split of 60/20/20. It's a High Carb, Low Fat diet.

Now remove 125g of carbohydrate to leave 250g of carbohydrate (1000kcals). It now adds up to 2,000kcals, with a percentage C/F/P split of 50/25/25. It's still a High Carb, Low Fat diet.

Now remove another 125g of carbohydrate to leave 125g of carbohydrate (500kcals). It now adds up to 1,500kcals, with a percentage C/F/P split of 33/33/33. It's now a Medium Carb, Medium Fat Zone diet.

Now remove another 62.5g of carbohydrate to leave 62.5g of carbohydrate (250kcals). It now adds up to 1,250kcals, with a percentage C/F/P split of 20/40/40. It's now a Low Carb, Highish Fat diet.

Now remove another 62.5g of carbohydrate to leave 0g of carbohydrate (0kcals). It now adds up to 1,000kcals, with a percentage C/F/P split of 0/50/50. It's now a Very Low Carb, High Fat diet.

So, 55g/day of fat can be Low Fat, Medium Fat, Highish Fat or High Fat. Which leads to...

3. Confusion

When someone sees the term LCHF (Low Carb, High Fat), they think it means "Eat less carbohydrate and eat more fat". As changes in bodily stores are determined by Energy Balance, eating more fat leads to a slower rate of weight-loss (or even weight-gain), not a faster rate of weight-loss.

By all means cut the consumption of "bad" carbs, like burgers in buns, chips/fries, crisps/chips, pizza, cake, biscuits/cookies, chocolate and sugar sweetened beverages.

However, if you believe that "good" carbs like vegetable produce, legumes, whole grains and whole fruits make you fat and sick, you need to have your head examined, unless you're in the tiny percentage of the population who have genetic carbohydrate intolerance.

See also Insulin Resistance: Solutions to problems.

Lies, damned lies and statistics, part n+1. Riera-Crichton et al.

In Macronutrients and obesity: Revisiting the calories in, calories out framework, the conclusion is:-
"Our structural VAR results suggest that, on the margin, a 1% increase in carbohydrates intake yields a 1.01 point increase in obesity prevalence over 5 years while an equal percent increase in fat intake decreases obesity prevalence by 0.24 points."

So, carbohydrates are fattening but fat is slimming, eh? I declare shenanigans! Two can play at that game.

In Effect of Dietary Protein Content on Weight Gain, Energy Expenditure, and Body Composition During Overeating, Bray et al increased kcals by 40% by adding Fat grams. Carb grams didn't change. Protein grams changed a bit. ∴ Protein %E & Carb %E decreased by ~29%. %E means "as a percentage of total Energy".

Weight (lean body mass + body fat) increased as Fat kcals increased ± some interpersonal variation.

From Fig. 6.

_
 _Decreased P %E & C %E result in increased weight.
∴ Increased P %E & C %E result in decreased weight.

∴ Fat is fattening, but Protein & Carbohydrate is slimming! Q.E.D.

Do you see what's going on? Here's a summary:-

Diet contains A, B and C.
The amount of A increases, but the amounts of B and C remain constant.
A%E increases, but B%E and C%E decrease.  

In Riera-Crichton et al, A = Carbohydrate, B = Fat and C = Protein.
In Bray et al, A = Fat, B = Carbohydrate and C = Protein.

Some fascinating healthcare statistics: Article by Ezra Klein.

Spotted on Twitter. From Is America better at treating cancer than Europe? , by Ezra Klein.

Healthcare rankings.

I highlighted Great Britain in green.

Cancer mortality.

Siri-Tarino et al, Forests & Trees and "Eureka!" moments.

Here's Fig. 2 from Meta-analysis of prospective cohort studies evaluating the association of saturated fat with cardiovascular disease:-

Risk ratios and 95% CIs for fully adjusted random-effects models examining associations between saturated fat intake in relation to coronary heart disease and stroke.

The above "Forest" plot has a subtotal RR of 1.07 (95% CI 0.96 1.19). The overall conclusion is that there's no association between saturated fat intake and the RR for CHD. Hmmm.

I looked at the data in Table 3. Of the 16 studies contributing to the CHD results, only 3 of them specify high sat fat intakes over a wide range. The results from these 3 studies are as follows:-

Pietinen et al: RR=0.93 (95% CI 0.6, 1.44).
Mann et al: RR=2.77 (95% CI 1.25, 6.13).
Boniface et al: Pooled RR = 1.37 (95% CI 1.17, 1.65).

The results from Pietinen et al are statistically-insignificant (95% CI values are way above & below 1) with an overall slight protective effect. The results from Mann et al have a RR >> 1 with both 95% CI's >1 and the results from Boniface et al have a RR >1 with both 95% CI's >1.

Other studies either have sat fat intakes varying from very low to low, or specify mean/median sat fat intakes without values for highest & lowest tertiles/quartiles/quintiles etc. Other studies have results that are statistically-insignificant.

However, there are some studies that show a slight protective effect of small amounts of sat fats. How come?

Thanks to George Henderson, I had a "Eureka!" moment. He posted a link to Dietary intake of saturated fat by food source and incident cardiovascular disease: the Multi-Ethnic Study of Atherosclerosis.

Here's Fig. 1 from that study.

HRs and 95% CI's of CVD risk according to quintiles of energy-adjusted SF from different sources (n = 5209).

The Meat SF plot has a net positive slope (bad news, but the range of intake is very small), the Butter & Plant SF plots are random, but the Dairy SF plot has a net negative slope (good news). Dairy saturated fats in amounts of up to 10g/day are protective against CHD. As the Dairy sat fat intake is too small to have a significant effect on lipids, what's the mechanism? I think that it's Vitamin K2. See Chowdhury et al, More forests & more trees and more "Eureka!" moments with cheese.

When you average out the results from all studies, the result is null. This is data dilution statistics.

EDIT: See also Study: Saturated Fat as Bad as Sugar!