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 :

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.

Why do the obese overeat ?

Another post inspired by a coincidence of two events - watching "65 Stone and Trapped In My House" and reading a couple of blogs after seeing Twitter references to them.

The TV programme was disturbing, to the extent where I nearly turned it off a couple of times. It centred on an obese man who had grown from 30 to 65 stone ( 910 lbs / 413 kg ) and become confined to one room in his own house and all but unable to move. Sadly the subject of the documentary died shortly after filming aged 33, from heart failure which was predicted by a bariatric surgeon who visited him for an assessment.

We saw the poor guy drinking full sugar pepsi while wallowing in his bed, and when his friends came round for dinner he wanted to eat the whole dish that they had made for sharing amongst five people.

Why does a man with at least 300 kg of fat stores feel the need to eat and drink 10,000 calories a day? When a dietitian suggested he would maintain at 7,000 and then should reduce by 1,000 per day in weekly steps he could not contemplate this and flat out refused - this was "too fast".

300 kg of fat stores is about 2.3 million calories so enough for 330 days energy supply at 7,000 a day. This is reminiscent of the infamous Scotsman "Mr AB" who did a water only fast for 342 days when faced with a similar dilemma - described here (including audio) and published by Stewart and Fleming. Unlike the unfortunate Carl Thompson (RIP) Mr AB lost 276 pounds, reaching his target weight of 180 pounds and maintaining the bulk of his weight loss. Over the five following years of observation, AB regained just sixteen pounds.

So what can we learn from a guy who on the night he died phoned a takeaway at 11pm to order apple crumble and two servings of ice cream, no doubt opening the conversation with his familiar "It's Carl and I'm starving". Was he suffering from persistent high levels of insulin, brought on by eating mountains of carbohydrate food, leading to much of his food intake being shuffled into fat stores leaving his metabolism still hungry ? This is the general statement of Gary Taubes' "Insulin Hypothesis" and further illustrated in Bob Briggs' Blog "Why are fat people hungry".

Bob quotes from the work of Dr Joseph Kraft who studies insulin levels and identified 4 patterns of insulin response to eating (the 5th pattern is minimal insulin response / Type 1 Diabetes) :

We know that fatter people generally have higher insulin levels and consequently release less fatty acids from storage into the bloodstream to use as metabolic fuel :

Also higher insulin levels reduce free fatty acid flux and concentration :

So the obese person with elevated insulin is denied access to the massive calorie reserves they are carrying and consequently live in a state of frequent hunger and consequent overeating with a proportion of what they eat being stored away as the carbohydrate portion further inhibits lipid oxidation.

The solution to unlocking the fat stores and reducing hungers lies in reducing insulin, through carbohydrate restriction and / or intermittent fasting. Even the Pattern 4 insulin response (green in the chart above) eventually falls after eating so a 16h fasting / 8h eating window approach may be beneficial.

The ketogenic diet, which is high in fat and low in carbohydrates, mimics the metabolic state of starvation, forcing the body to utilize fat as its primary source of energy. This also results in reduction in insulin levels. Once adapted to such a diet the consumers of an LCHF diet with moderate protein are, in general, not hungry, and frequently under-eat in clinical studies.

Evidence that carbohydrate restriction mimics total fasting has been provided by clinical studies where infusing lipids into the bloodstream at a rate equivalent to the Basal Metabolic Rate have little effect on outcomes - "carbohydrate restriction, not total energy restriction, is responsible for the increase in lipolytic sensitivity observed during fasting". S Klein and RR Wolfe have published several studies looking at lipolysis rates and the influence of various parameters on those rates.

From this and other reading I am drawn to conclude that :

1. Lack of fat release from storage leaves the fat person needing to eat for energy supply. Persistent hunger is a powerful motivator especially in the lonely or depressed.
2. Eating carbohydrates elevates insulin and reduces fat oxidation, reducing use of fats as well as their availability.
3. Elevated insulin responsible for locking up the fat also stores further dietary fat on the body. Eating carbs and fat together maximises this effect.
4. Carbohydrate restriction or fasting allows insulin levels to fall and unlock the fat reserves.
5. People on total fasts or 500-800 calorie modified fasts, or carbohydrate restriction to ketogenic levels, are not hungry and therefore do not typically overeat.

Ironic Nutritional Ketosis

A couple of years ago I had an enjoyable 1 week holiday at Jason Vale's mountain retreat in Turkey aka "Juicy Mountain". Jason is a "juicing guru" who advocates freshly juiced fruits and vegetables for health and combines this with vigorous exercise programmes and yoga in a stunning setting to give a cleanse of mind, body and soul. To be honest I was somewhat skeptical as I am no spiritualist or gym bunny and after 3 years of low carb eating I thought I may need counselling to go on a diet that was substantially carbohydrate based.

I took along my blood glucose and ketone testing kit but left most everything else electronic behind, in order to de-stress and "be present" as Becky the retreat manager requested we should be. We ate practically no food during the week but started each day with yoga followed by a small juice shot and then a long walk or similar. On returning there may be a gym or rebounding (trampoline) session before the first real juice of the day at 10am. After that came more exercise in the gym with the brilliant Tim Britton as our trainer and other less formal exercise like volleyball, swimming or borrowing the mountain bikes. Another juice at about 1pm preceded the relaxing afternoon in the 30+ degree C heat (90 F) before we were back in the gym or on the trampolines followed by "tea" at around 5pm and a final juice watching a DVD or similar at about 8pm. Yoga was led by Ken Ryan, a brilliant Irishman with a level of quirky charisma that only the Irish can aspire to, as demonstrated by him living in an actual cave on the mountainside.

Looking back I can identify several elements that contributed to my 7 pound / 3.2 kg weight loss during the week. Firstly we had a sort of intermittent fasting regime where we had virtually no calorie intake between 8pm and 10am the following day. In the morning we had yoga and exercise in a fasted state, walking for an hour up and down hills or doing a 5km run down and back up the mountain. Overall the calorie expenditure was high with several hours of physical activity per day and there was presumably a fairly low calorie intake from drinking about 1.2 - 1.5 litres of juices and blended smoothies per day as our sole "food" intake.

I estimate I was taking in around 1,000 calories a day (+/- 20%) with probably 80% from carbohydrate and when I used my Polar heart rate monitor I estimate my daily exercise was at least 2000 calories, most of which was in temperatures above 30 degrees C.

So to the numbers, below. I took a couple of baseline readings at home, then after flying to Turkey and arriving late at night a couple of readings on our first day in the retreat. The second reading was just before the evening juice and I followed that up with 3 half hourly glucose tests to see the postprandial effect of the juice - which was less alarming than I expected.

Date	28/08/2013	29/08/2013	31/08/2013	31/08/2013	31/08/2013	31/08/2013	31/08/2013	31/08/2013
Time	18:00	17:00	07:30	17:20	17:46	18:18	18:48	19:18
Glucose mmol/l	5.4	4.4	5.9	4.0	4.6	6.5	5.9	6.3
Ketones mmol/l	0.8	0.3	0.8	0.4
Ratio G/K	6.8	14.7	7.4	10.0
Notes	UK	UK	Turkey	End of day	Juice time	------ post juice drink testing ------
UK time off meter
Date	01/09/2013	01/09/2013	02/09/2013	03/09/2013	04/09/2013	05/09/2013	05/09/2013	06/09/2013
Time	04:47	11:02	05:15	05:31	04:09	05:00	06:40	04:15
Glucose mmol/l	6.3		5.8		5.3	5.8		4.9
Ketones mmol/l	1.6	2.3	2.8	2.4	2.9	1.4	0.6	3.4
Ratio G/K	3.9		2.1		1.8	4.1		1.4
Notes					Boat trip		after run

The days in September I mainly took a fasted reading on waking at dawn - we were "sleeping" in a very warm tent so tended to be up very early. The ketone levels I recorded were typically over 2.0 which is quite unusual for me, hence the 11:00 check on the second day. Google sheets link to data.

On the Thursday we had a "day off" with an excursion down to Gocek -

 

and a boat trip where the enthusiastic captains of our boats provided us with quite a lot of fruit to eat and tomatoes with salt which proved very popular indeed - the group nicknamed themselves "Salty Tomatoes" after the primal behaviour displayed getting to the salt from the guests who were going through "keto flu" symptoms as they adapted (or failed to adapt) to the reduced carbohydrate and low calorie intake.

My ketone levels halved after the boat trip which I thought at the time was due to the high sugar intake from the fruits, although the reduced activity level may also have been a factor. Our juices at the retreat had a high vegetable content and blended avocado so I think the boat trip food was probably a bad idea in the middle of a week of otherwise controlled intake. I suspect the trip and fruit is a necessary part of the retreat programme in order to stop people fleeing to buy food or to escape from the isolated mountain location.

The day after the boat trip we started our morning with a 5km run down about 500' of fairly rough mountain tracks and back up again. This was a repeat of a run done at the beginning of the week to assess our progress. My ketone levels after the run were low, perhaps because I had been using them or perhaps a continuation of the alleged effect of the boat trip. Either way I was back up over 3 the next and final morning before departure.

So that's the long overdue story of how a low carb eater lived the juicy life for a week and saw improved levels of blood ketones despite a predominantly carbohydrate diet at restricted calorie intake. I lost 7 pounds and fell below 12 stone (168 lbs / 76.3 kg  - I am 5'-10" / 1.80m) for the first time I can recall as an adult, I did exercise beyond any previous experience and had a really good time thanks to the excellent team in place at the resort and my fellow travellers.

Better results from low carb than lower fat.

 There's a lot of chatter over the pond and on t'internet about a recent study comparing low carbohydrate diet advice with reduced fat.

The work was led by Drs Bazanno and Hu of Tulane University, New Orleans and funded by the US National Institutes of Health. Its stated objective was

to examine the long-term effects of a diet low in carbohydrates, as compared to one low in fat, on cardiovascular disease risk factors, including blood pressure (BP), body weight and composition, serum lipids, plasma glucose, insulin, adipocytokines (adiponectin, leptin, resistin), and C-reactive protein (CRP) among obese adults.

All calories are not equal

I was recently drawn to read a report of a clinical trial of over-feeding, conducted by Bray et al of Pennington Biomedical Research Center. This was an inpatient study looking at the effect of protein on weight gain in people eating 40% more calories than required for maintenance of body weight.

This study was brought to my attention as evidence that the number of calories is more important than the composition of those calories, and it was said that "all the extra calories were from fat". On further examination I found that it actually shows something different.