Everyone's a fruit and nut case

Earlier in the week I awoke to the radio pronouncing that eating fruit was better than eating nuts, or some such. Google turned up a Swedish study "A Randomized Study of the Effects of Additional Fruit and Nuts Consumption on Hepatic Fat Content, Cardiovascular Risk Factors and Basal Metabolic Rate" by Christian Agebratt et al.

This study set out to compare the effects of adding about 500 calories a day of either fruit or nut intake to the existing diet of some young lean active healthy Swedish students. The primary objective was to see if the sugar in the fruits had any adverse effect.

Chef succeeds on Atkins Diet

Another personal testimony from the Atkins UK forum :-

Hi Folks,

A have been following some of the threads on this forum for a couple of months now but have not posted until now, so this is my first post here. 

Atkins Diet success story

Shirley, age 63 and with hypothyroidism, reports a weight loss of 6 stone / 84 lbs / 38 kg in 17 months through following the Atkins diet without exercise and with support from the Atkins UK community forum. That's an average loss of over 1.2 lbs per week.

Here's her story in her own words......

Carbohydrate Restriction for Type 2 Diabetes.

We are often told to look to the £m charity Diabetes UK for dietary and other advice on receiving a diagnosis of Diabetes. As a pre-diabetic (HbA1C 38 mmol/mol or 5.8 % in old money) I did this and prepared a short summary :-

Hall shows greater weight loss on reduced carbohydrate

Data mining in Hall (2015) and ignoring the press and social media nonsense storm I find that in the (insulin sensitive) men the measured fat loss using the gold standard (?) DEXA method was actually marginally greater on the reduced carbohydrate diet :

Short term weight loss in insulin sensitive men

Digging further into Kevin Hall's study it is apparent that the men and women were substantially different in terms of Insulin Resistance, Insulin and Leptin levels. The men average a HOMA-IR of 2.2 but the women average 3.3 putting the two genders either side of the 2.7 Insulin Resistance cut-off used in Brazil. Fasting insulin was 50% higher in the ladies and fasting leptin 2.5 times higher, but fasting blood glucose was the same in both at 88 mg/dl / 4.9 mmol/l.

The men tended to be older (38 vs 33) and less obese (34 vs 38 BMI) with p-value 0.15 or lower but not reaching statistical significance (9 women and 10 men is a modest sample size).

We need to talk about Kevin (Hall)

A few months ago I chewed over a poster presentation by Kevin Hall and associates which presented the findings of a detailed metabolic comparison over six days of an 800 calorie intake reduction of either carbohydrate or fat alone in a crossover design. I was concerned about an apparent imbalance in calories / carbohydrate balance that suggested the reduced carbohydrate (RC) phase was depleting glycogen reserves and hence the study was not of a steady state condition.

I general I like the work done by Hall as I have a similar modelling background. There are however remaining concerns now that the full version of the paper has been published in Cell Metabolism.

Firstly I would like to address the "pictorial abstract" :

On the left we can presume that the ~800 kcal/day reduction in dietary fat intake was replaced by fat from body stores, as everything else is shown as the same. At 9.4 kcal/g that's a fat loss of 85 grams/day which is in line with the stated "89 ± 6 g/day of fat loss" for the RF diet (at 9 kcal/g it's a near exact match). So far so good.

On the right life gets complicated. The reduction in carbohydrates allows fat oxidation to flourish to the tune of +400 kcal/day - the reason people like me favour carbohydrate restriction. So the subjects are burning 400 more of fat but 500 less of carbs and hence energy consumption has dropped by about 100 kcal/day. Although burning 500 kcal less of carbs the intake of CHO has been reduced by 800 kcal - so 300 kcal  ( 81 grams/day) has appeared out of the woodwork, or more likely out of the body's glycogen stores.

With 300 kcal of bonus fuel entering the mix the fat loss of the restricted carb diet is impaired - with the same fat intake it relies on increased oxidation and this only rose by ~400 kcal/d which is indeed only half of the reduction of intake seen in the fat restricted phase.

The question remains as to how long this condition could be sustained before the additional carbohydrate reserve dried up and forced a further increase in oxidation of fat. A study for 6 days isn't even half of the Atkins induction phase and the carbohydrate intake here was ~140 g/day which is well north of any "Low carbohydrate" diet let alone anything ketogenic.

A secondary question arises from the fact that supplementary table S3 shows that there was no significant fat loss in the female subjects on either diet - in fact their % body fat went up (NS). I shall be returning to this study to focus on the men who did at least lose weight and reduce their fat mass significantly. I always prefer single gender studies as so much variability is added and significance lost by combining men and women.