Monday, September 23, 2013

Paleolithic Diet Trials: Part 2


13 patients (10 males, 3 females) with type 2 diabetes and without insulin treatment. 

This study was a crossover trial.  For this study it means the subjects were randomised to two groups, then one group goes on the Diabetes diet first and the Paleolithic diet second, and the other group goes on the Paleolithic diet first and then the Diabetes diet second. 

Group A
Group B
Month 0-3
Diabetes diet
Paleolithic diet
Month 3-6
Paleolithic diet
Diabetes diet

Diets: 

Paleolithic diet
“The information on the Paleolithic diet stated that it should be based on lean meat, fish, fruit, leafy and cruciferous vegetables, root vegetables, eggs and nuts, while excluding dairy products, cereal grains, beans, refined fats, sugar, candy, soft drinks, beer and extra addition of salt. The following items were recommended in limited amounts for the Paleolithic diet: eggs (≤2 per day), nuts (preferentially walnuts), dried fruit, potatoes (≤1 medium-sized per day), rapeseed or olive oil (≤1 tablespoon per day), wine (≤1 glass per day). The intake of other foods was not restricted and no advice was given with regard to proportions of food categories (e.g. animal versus plant foods). The evolutionary rationale for a Paleolithic diet and potential benefits were explained” 

Diabetes diet
“The information on the Diabetes diet stated that it should aim at evenly distributed meals with increased intake of vegetables, root vegetables, dietary fiber, whole-grain bread and other whole-grain cereal products, fruits and berries, and decreased intake of total fat with more unsaturated fat. The majority of dietary energy should come from carbohydrates from foods naturally rich in carbohydrate and dietary fiber. The concepts of glycemic index and varied meals through meal planning by the Plate Model were explained. Salt intake was recommended to be kept below 6 g per day.” 

Foods higher in Paleolithic diet
Foods higher in Diabetes diet
Fruits
Potatoes
Vegetables
Beans*
Meat
Cereals without rice
Eggs
Milk/milk products
Bakery*
* Significant, yet small differences 
Macronutrients
Paleolithic diet
Diabetes diet
Energy (kcal)*
1581
1878
Protein (%)*
24
20
Fat (%)*
(SFA*/MUFA/PUFA (g))
39
(19 / 30 / 14)
34
(27 / 26 / 12)
Carbohydrate (%)*
32
42
Alcohol (%)
3
1
Fibre (%)
2.5
2.7
* Significant differences 
Micronutrients
Paleolithic diet
Diabetes diet
Vitamin B6 (mg)
3.2
2.4
Vitamin C (mg)
219
119
Niacin (mg)
27
22
Phosphorous (mg)
1233
1437
Potassium (mg)
3669
3181
Calcium (mg)
356
698
Selenium (µg)
81
55
* Only includes significant differences 
See table 5 

The Paleolithic diet provided more nutrition than the Diabetes diet, even though it contained 16% fewer calories. 

Results: 

Cardiovascular Risk Factors 

The following table lists the CV risk factors where the Paleolithic diet produced a significant difference between groups and baseline, where the results are the averages across both groups after 3 months on the Paleolithic diet and the Diabetes diet.  Italics indicate a non-significant difference compared to baseline 

Paleolithic
Diabetes
HbA1c (%)
5.5
5.9
HDL (mmol/l)
1.34
1.26
Triglycerides (mmol/l)
1.0
1.5
DBP (mmHg)
79
83
BMI (kg/m2)
28
29
Waist (cm)
94
98

Compared to baseline, the Paleolithic diet also improved fasting glucose, fasting insulin, AUC glucose, the insulin sensitivity index and HOMA IR, whereas the Diabetes diet did not 

See table 3 

You can see the results from the first table in the graphs below, which came from figure 1.  Closed circles depicts the group starting the Diabetes diet first and open circles depicts group starting the Paleolithic diet first.  I added ‘D’ and ‘P’ to make it easier to read


“In exploratory analyses of primary endpoints, within-subject differences (Δ) in HbA1c (ΔHbA1c) correlated with Δwaist circumference, which correlated with Δweight, which correlated with ΔCRP. Furthermore, ΔHDL correlated with Δcholesterol and ΔDBP with ΔHOMA2 IR. In exploratory analyses of estimated intake of nutrients, ΔHbA1c correlated with Δpotassium, ΔHDL with Δfatty acid C20:5 n-3, ΔTG with Δthiamin, ΔDBP with Δdietary cholesterol, Δweight with Δenergy density per meal, and Δwaist circumference with Δbakery, Δenergy density per meal, Δsauce and Δvitamin E”.  See table 6 

Satiety and Other Experiences 
Like the other trial, there was no significant difference between the groups in the time between meals (~3 hours), the meals per day (~5) and reported satiety before and 30 minutes after the meal.  The difference was in the number of calories it took to reach a given level of satiety. 

Paleolithic
Diabetes
Energy from good and drink per day (MJ)
1581
1878
Satiety quotient for energy per meal (RS/MJ)*
1.8
1.5

* The change in satiety before and after the meal divided by the energy content of the meal 

See table 1 

“In post hoc analysis of within-subject differences (value during Paleolithic diet minus value during diabetes diet), satiety quotients for energy per meal correlated with triglyceride levels and vitamin B6 intake, satiety quotients for energy density per meal correlated with water from food.”  See table 2

The patients were given a survey to comment how they found the diets.  You can find the results of the survey here.  They found mostly positive comments for both diets and that the Paleolithic diet was better for weight loss, but harder to stick to.  See table 3 
The Discussion and Some Thoughts

Cardiovascular Risk Factors

“The lower DBP after the Paleolithic diet compared to the Diabetes diet did not correlate with sodium intake, which did not differ significantly and was rather low in both diets (2.5 g and 3.0 g per day respectively for the Paleolithic and Diabetes diet).”  Instead, reductions in DBP were correlated with improvements in insulin sensitivity (HOMA2 IR), which is exactly what you would expect.  That being said, don’t place too much importance on the associations.  For example, potassium is probably only associated with HbA1c because it was higher in the Paleolithic groups and is a marker of fruit and vegetable intake and compliance 

Satiety and Other Experiences

The survey results are interesting.  What stuck out for me was: 


  • 3 people said their weight or glucose got worse after the diabetes diet
  • One person said they were always hungry on the Paleolithic diet, even though both diets were ad libitum*
  • A few people missed bread and dairy (mostly cheese) on the Paleolithic diet
  • A few people mentioned the lack of salt on the Paleolithic diet, which is surprising because there wasn’t a large difference in sodium intake (2530 vs. 2963 mg) and if you adjusted for calorie intake the numbers are almost the same (I don’t know why, perhaps because of higher potassium?  At least this is an unnecessary restriction in my opinion) 

* I think this is because people overestimate the number of calories of ‘Paleo’ foods, or simply have no idea.  They might put together a piece of lean meat, some non-starchy vegetables and a piece of fruit and call that a meal.  That’s a really nutrient dense meal, but it’s only about 300 calories.  If you’re eating those sorts of meals you’re going to get hungry.  Another example is snacks.  A common snack of a donut/muffin/chocolate/whatever and soft drink/coffee with cream and sugar is easily a few hundred calories, if you go Paleo and your snack is an apple and a glass of water that’s only about 100 calories.  Unless you go down the ‘stuff swimming in butter’, ‘bag of nuts a day’ or ‘Paleo junk food’ path, not eating enough calories is probably a more likely problem than eating too many (ironically).

2 comments:

  1. I just wanted to point out there were only three women in the study, so we can't be very certain the results apply to type 2 diabetic women in general.

    -Steve

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    Replies
    1. True. The other trial was all men, don't know why. It's a shame the number of participants in both trials was so small as well

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