Tuesday, 29 December 2015

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. 

Saturday, 10 October 2015

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......

Sunday, 23 August 2015

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 :-

Monday, 17 August 2015

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 :

Saturday, 15 August 2015

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).

Friday, 14 August 2015

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.

Monday, 3 August 2015

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.

Wednesday, 29 July 2015

Type 2 Diabetes - dietary advice from Diabetes UK

A couple of weeks ago I received an e-newsletter "Type 2 Together" about peer support for Type 2 diabetics arranged by the charity Diabetes UK. It featured a recipe :

One slice of this contains at least 4 times the amount of glucose in my bloodstream, so I am somewhat confused as to why this would be a good recipe for Type 2 diabetics. Perhaps it's because it is low in fat. That's right, patients with an excess of carbohydrate in their bloodstream and a problem managing it are apparently supposed to be primarily concerned about fat, so at least there's only 1g per slice.

The ingredients aren't exactly inspiring - mixed fruit, wholemeal flour and fructose - or sugar, sugar and sugar for simplicity.

Around the same time Diabetes UK were running a PR campaign about the number of foot amputations occurring in the UK diabetic population. As I understand it the foot amputations result from diabetic neuropathy, which is caused by elevated blood glucose, which in turn is caused by digesting carbohydrates.

If we're worried about foot amputations, why not suggest eating less carbohydrate !

The hand wringing about fat arises from increased heart disease in diabetics. I would imagine this is entirely due to the effects of elevated blood sugar on the cardiovascular system, so once again carbohydrate restriction would appear to have some merit.

I used the UKPDS risk calculator to estimate the effect of HbA1c on my personal heart disease risk over 10 years. With all other variables constant the risk rises with HbA1c :-

HbA1c %        10 year risk %
4                              4.7
5                              5.5
6                              6.5
7                              7.6
8                              9.0

So reducing HbA1c from 8 to 4 brings a corresponding halving of the heart disease risk. Once again, does this not suggest less blood glucose is good for the heart ? Especially when low carb diets also improve the CVD risk profile by increasing HDL cholesterol and reducing triglycerides.

Whichever way I look at it the Diabetes UK cake recipe and their dietary advice in general is a recipe for heart disease and amputations.

Tuesday, 21 July 2015

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.

Glucose mmol/l5.
Ketones mmol/l0.
Ratio G/K6.814.77.410.0
NotesUKUKTurkeyEnd of dayJuice time------ post juice drink testing ------
UK time off meter
Glucose mmol/l6.
Ketones mmol/l1.
Ratio G/K3.
NotesBoat tripafter 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.

Thursday, 9 July 2015

BBC Inside Health - Gestational Diabetes, Low Carb Dieting.

A recent edition of BBC Radio 4's "Inside Health" programme covered gestational diabetes and (separately) the experiences of a listener who lost 4 stone (56 lbs, 25 kg) on a low carbohydrate diet.

The programme web site is here, and the mp3 audio file should be available to download via this link however BBC media can be time or location limited so I apologise if it isn't available to you. I do have a copy of the mp3 so get in touch if you need one.

The gestational diabetes (GDM) item was based on the Rosie Hospital in Cambridge where they have recently published work on the sensitivity of different diagnostic criteria for GDM. The article in Diabetologia identifies patients with GDM who fall between the UK's NICE guidance on diagnosis and other criteria and looks at the risks of complications in that group. Full paper here.

Of interest to low carbers was the clear description by a dietitian on air as to how all carbohydrates including starch end up as blood sugar. She went on to say that this meant the hospital encouraged mothers-to-be to change from white bread to wholemeal as the lower GI reduced the blood sugar impact, which was a bit of a let down after a good start. Dr Mark Porter, who presents the program, said on Twitter that the Rosie Hospital's GDM program used diet and carbohydrate restriction, along with exercise, as its primary treatment method. Unfortunately this didn't come over in the audio, perhaps due to editing, so the message was more about changing the colour of your bread rather than eating a lot less of it in the first place.

The second item of interest concerned a listener Mark Robbins who called in to enthusiastically report his weight loss on a low carb diet. Dr Mark discussed this with regular sidekick Dr Margaret McCartney (a GP from Glasgow) and the eminent Professor Susan Jebb OBE. There was a general consensus that low carb dieting does work and that Drs Mark and Margaret see this in their practice patients. It was also agreed that diet trials of up to a year - said to be "short term" - support low carb dieting. Unfortunately nobody much does long term studies, perhaps due to cost or the difficulty of keeping subjects motivated and under control for so long.

Dr Mark asked (at 20m48) if there was a scientific reason / rational explanation of why low carb diets might make weight loss easy and Prof Jebb replied to the effect that "it is just about calories". Perhaps she needs to sit in on Metabolism or Biochemistry 101 classes and remind herself how chronic carbohydrate consumption elevates insulin which impairs the release and oxidation of fat from storage. To lose 25kg of fat in a year requires a fat oxidation rate of 2,9 grams per hour average above the dietary intake (or bodily production) of fat - that's about 25 calories an hour or 600 calories a day and probably 25% of the calorie burn of the listener. Clearly anything that increases fat release and fat oxidation rates is a good thing when you want to achieve this - carbohydrate ingestion does the opposite.

Speaking of Dr Jebb, she appears on the author list of a recent study "Dietary patterns, cardiometabolic risk factors, and the incidence of cardiovascular disease in severe obesity" which looked at 2000 Swedish subjects over 10 years. After much complex maths they concluded "An energy-dense, high-saturated-fat, and low-fiber DP was longitudinally associated with increases in cardiometabolic risk factors in severe obesity but not with CVD incidence" (my emphasis) so once again the "saturated fat is bad" mantra did not stand up to analysis, neither did the "high fibre" approach that Prof Jebb is so keen on. She will never be in favour of low carb diets while she's locked into a high fibre from whole grains and low saturated fat dogma that is increasingly looking "so last century".

Who eats whole grains ? Only pigeons, as far as I can see. Sorry Susan.




If you’re a vegetarian or vegan, whole grains and starchy vegetables may have traditionally been important components of your meals. These are the foods that you’ll reintroduce in Phase 3, Pre-Maintenance. However, they’re also some of the very foods that may have gotten you in trouble in the past. You may find that over time you can tolerate larger portions as long as you steer clear of refined grains and most processed foods.

Advice for Vegetarians and Vegans

  • Follow the general guidelines for reintroducing foods at the top of the Carb Ladder.
  • Follow the basics for Pre-Maintenance and for doing Atkins as a vegetarian or avegan
  • Always eat carbohydrates with fat and/or protein.
  • Add back starchy vegetables followed by whole grains before higher-carb fruits (other than the berries and melon acceptable in OWL). 
  • Continue to focus on foundation vegetables.
  • Regard starchy vegetables and whole grains (and legumes) as side dishes, rather than the mainstays of a meal.
  • Avoid white rice, white flour and other refined grains.
  • Use Atkins Cuisine pasta, Shirataki pasta or whole-grain pasta instead of conventional pasta made from white flour.
  • Bake with Atkins Cuisine All Purpose Bake Mix or soy flour instead of white flour.
  • Continue to use low-carb productssuitable for Ongoing Weight Loss.

[ Reproduced without permission from now-defunct page on Atkins.com - links may not work ]

Atkins for Vegans

Atkins for Vegans

It’s challenging for vegans, who don’t eat eggs and dairy products, to do Atkins, but not impossible. The trick is to get sufficient protein from seeds, nuts, soy products, soy and rice cheeses, seitan, legumes and high-protein grains such as quinoa. Weight loss may proceed more slowly because of the higher carb intake than that of those following the standard Atkins program. Vegans should make the following modifications:
  1. Start in Ongoing Weight Loss at 50 grams of Net Carbs so that you can have nuts, seeds and their butters, plus legumes, from the start.
  2. If you don’t have much weight to lose, start in Pre-Maintenance at 60 grams of Net Carbs, in order to include small amounts of whole grains and starchy vegetables from the start.
  3. Make sure you’re getting sufficient protein in plant sources.
  4. In order not to interfere with fat metabolism, add extra flaxseed, olive, canola, walnut and other oils to salads and vegetables to make up for the smaller amount of fat in most of your protein sources.
  5. Shakes made with plain unsweetened soymilk (or almond milk), soy (or hemp) protein, berries, and a little sweetener can make a tasty breakfast. Add some coconut milk to up the fat content and make the shake creamer.
  6. You can also make shakes with silken tofu. Try it puréed with peanut or almond butter for added protein and fat.
  7. Sauté silken tofu with onions and other vegetables to stand in for scrambled eggs.
  8. Mayonnaise made with soy instead of eggs, mixed with crumbled tofu, chopped celery and onions, and a little curry powder makes a tasty eggless salad.
  9. Silken tofu and soy creamer can be used in desserts, as can agar-agar in jellied desserts.  

When you move to Pre-Maintenance, follow the general guidelines for reintroduction and think of these foods, as well as legumes, as side dishes, rather than the mainstays of a meal. You may find that over time you can tolerate larger portions as long as you steer clear of refined grains and most processed foods. Add back starchy vegetables followed by whole grains before higher-carb fruits (other than the berries and melon acceptable in OWL). Continue to stay away from conventional pasta and other products made with white flour and other refined grains.

[ Reproduced without permission from now defunct Atkins.com web page ]

Atkins for Vegetarians

This is a copy of the content of a now-defunct page from the atkins.com web site, the links may not work but it is reproduced here for information.

The Program: Ways to Create a Custom Diet Plan, With Atkins

Atkins for Vegetarian

It’s perfectly possible to be a vegetarian—or simply minimize your intake of animal protein, add variety to your meals and trim your food budget—and still do Atkins. The typical American vegetarian often consumes far too many carbohydrates in the form of pasta and other refined grains. As long as you have at least two varieties of plant protein each day, you can get a balance of essential amino acids (the building blocks of protein). Which leads to the second challenge. Plant proteins are “packaged” with carbohydrate. Your objective is to consume enough protein without simultaneously getting so much carbohydrate that it interferes with weight loss or weight maintenance.

To adapt Atkins to your needs as a ovo-lacto vegetarian:

  1. Start in Phase 2, Ongoing Weight Loss (OWL), at 30 grams of Net Carbs and introduce nuts and seeds and all unsweetened dairy products except milk (whether whole, skim, low fat, or no fat) and buttermilk before berries.
  2. Or, if you have no more than 20 pounds to shed and are willing to swap slower weight loss for more food variety, you may start in Phase 3, Pre-Maintenance, at 50 grams of Net Carbs.
  3. Make sure to get sufficient protein in eggs, cheese and soy products. Aim for no more than 6 grams of Net Carbs per serving of protein foods in OWL.
  4. Meat substitutes may be made from textured vegetable protein (TVP), soy protein (tofu and tempeh), wheat gluten (seitan), and even fungi (Quorn) among other ingredients. See Acceptable Induction Foods: Soy and Vegetarian Products for a more comprehensive list. Some of these products contain added sugars and starches and some are breaded, so read the list of ingredients carefully.
  5. Get most of your carbs from foundation vegetables.
  6. Most nonanimal protein sources (except for tofu and nut butters) are low in fat. Continue to get enough healthy oils in other dishes by dressing vegetables and salads with olive oil, canola oil, high-oleic safflower, walnut, flaxseed and other oils so as not to interfere with fat metabolism Also enjoy high-fat snacks such as half a Haas avocado or some olives.
  7. Add back nuts and seeds before berries. Nuts and seeds contain fat and protein that will make Atkins easier to do and more effective.
  8. Or, if you choose, add back legumes before other OWL-acceptable foods. But do so in extreme moderation (2-tablespoon servings), using them as garnishes on soups or salads.
  9. Tempeh, made with fermented soybeans, is higher in protein than tofu and more flavorful. Sauté tempeh with veggies in a stir-fry, crumble it into chili, soup, or sauces or marinate and grill it. Avoid tempeh products that include rice or another grain until you’re in Pre-Maintenance.
  10. Shakes made with plain unsweetened soymilk (or almond milk), soy (or hemp) protein, berries and a little sweetener can make a tasty breakfast.
  11. Purée silken tofu with berries and other fruit in shakes, adding peanut or almond butter for added protein; or sauté firm tofu with vegetables for lunch or dinner.

If you eat no eggs and dairy:

  1. Substitute crumbled silken tofu for scrambled eggs—a pinch of turmeric provides an appealing yellow hue. For baking, use an egg substitute product.
  2. Even some vegetarian products, such as Quorn, as well as shakes, may contain eggs or whey. Read labels carefully.
  3. Mayonnaise made with soy instead of eggs, mixed with crumbled tofu, chopped celery and onions, and a little curry powder makes a tasty eggless salad.
  4. Silken tofu and soy creamer can be used in desserts, as can agar-agar in jellied desserts.
For more ideas, see Atkins for Vegans.

Pre-Maintenance and Beyond

Whole grains usually loom large for vegetarians, and starchy vegetables are often important components of meals. However, they’re among the very foods that may have gotten you in trouble in the past. Follow the general guidelines for reintroduction and think of these foods, as well as legumes, as side dishes, rather than the mainstays of a meal. You may find that over time you can tolerate larger portions as long as you steer clear of refined grains and most processed foods. Add back starchy vegetables, followed by whole grains, before higher-carb fruits (other than the berries and melon acceptable in OWL).

Tuesday, 10 March 2015

Book review may signal change is in the air

A book review may not be a policy statement, but it may reveal some of the thinking and views of the reviewers. The review in question is that of Nina Teicholz's journalistic tome "Big Fat Surprise: Why Butter, Meat & Cheese Belong in a Healthy Diet" which explores and exposes the background and evolution of current dietary guidelines. Nina herself halved her blood triglycerides by switching to a diet of "60% fat (plenty of it saturated), 25% protein and 15% carbohydrates" however it should be noted that she is an investigative writer rather than a research scientist or n=1 experimenter.

The authors of the review are Debbie Cook and David Haslam of the UK's "National Obesity Forum" - "Debbie Cook is the Vice Chair at National Obesity Forum, and a Nurse Practitioner and Clinical Nurse Manager" and Prof David Haslam is the Chair of the National Obesity Forum and  the eminent non-executive Chair of the UK's National Institute for Health and Care Excellence (NICE).

It seems likely, or at least possible, that the review will disappear in a storm of controversy, but some of the interesting extracts are :-

The UK is ready for the revelation that sugar is toxic, and that refined carbohydrates and fruit juice are detrimental to health, and has taken it fairly well. But the next big shock wave – that another macronutrient is an important, healthy and necessary part of the diet: namely saturated fat – may take some swallowing. 
 In a meticulously well researched book, we are informed and educated about why the modern world faces an epidemic of obesity, why generations of Americans religiously followed the nutritional dogma fed to them by researchers of questionable integrity.

Does low fat diet give faster fat loss than low carb ?

A recent Poster presentation (ie not fully peer reviewed published science) posed the question

"Is a Calorie a Calorie? Metabolic Fat Balance Following Selective Isocaloric Restriction of Dietary Carbohydrate Vs. Fat in Obese Adults. - Kevin D Hall et al.
and went on to describe a clinical study where about 800 calories of either fat or carbohydrate were removed from the diet of the same group of subjects in a crossover design. So the grams of protein stayed the same, and in the low fat arm the grams of carbohydrate stayed the same with the fat remaining constant in the low carb arm.

This is quite a good design, as it saves protein changes having an effect. It does constrain the low carb arm to a relatively high carbohydrate content (30%) because the caloric reduction takes the fat in the low fat arm down to only 7% or 15 grams a day.

From the limited data in the abstract I have tried to calculate the average intakes :-

Baseline Low Carb Low Fat
Calories/day (kcal) 2720 1930 1920
Carb energy % 50 30 72
Fat energy % 35 49 7
Protein energy % 15 21 21
C grams 340 145 346
F grams 106 105 15
P grams 102 101 101

During the experiment the subjects spent time in a metabolic chamber where gas analysis, temperatures and airflow measurement allows calculation of their metabolic rate and the proportion of their energy supplied by fat and carbohydrate. The authors used this data to calculate the fat loss based entirely on "fat exhaled" rather than traditional weighing and body composition analysis.

After 5 days on the baseline diet the subjects were allocated to either Low Carb or Low Fat for 6 days, then returned after two weeks to repeat the baseline diet and the opposite arm of the calorie reduction. Weight loss was greater on low carb than low fat, 1.9±0.2 vs. 1.3±0.1 kg; p=0.05. That's more than a pound greater in less than 6 days, this is often seen as the initial weight loss of water due to carbohydrate restriction and its diuretic effect.

Despite the greater weight loss on low carb, the authors report that "body fat loss was ~67% greater after 6 days of LF vs. LC (394±40 vs. 236±30 g; p=0.0003)." At 9 cals/g that equates to 591 cals/day on LF and 354 cals/day on LC. To try and understand why, and where the apparent energy imbalance occurs, we need to calculate the oxidation rates ( "burning" ) of carbs and fat. We'll do this by assuming that the food being eaten is oxidised at the same rate and that additional energy is supplied from body reserves :-

Calories expended 2720

Change in cal exp reported -72 -81
Extra fat burn cals
426 -53
Extra fat burn grams
47 -6

Fat Oxidation grams 106 153 100
Fat Balance in – out 0 -48 -85
Difference LC – LF

Total body fat loss g reported 236 394
Per day grams 5 47 79
Extra LF vs LC


Calories expended 2720 2648 2639
From fat kcal 952 1378 899
From protein kcal 408 405 403
From carbs kcal 1360 579 1382

Accounted for kcal 2720 2362 2685

Discrepancy kcal 0 286 -46
as fat grams
as carbs grams

The two diets both saw a small but similar calorie expenditure reduction from baseline of 72 and 81 calories a day. Fat oxidation increased significantly on the low carb diet giving 50% more fat burn but the extra 47 grams/day is less than the 90 grams a day taken out of the low fat diet.

Adding up the oxidised fat, protein and assuming that the carbs eaten were oxidised gives the "Accounted for kcal" row above, as the paper didn't report carbohydrate oxidation rate. There's a shortfall of 286 calories/day in the low carb case as not enough fat is being burned to provide the measured energy output. 

Without access to more data the best explanation I can offer is that the discrepancy was supplied by about 70 grams of carbohydrate oxidation from glycogen reserves - a transient resource that would not have lasted many days at this rate. Had the experiment continued for another week then glycogen would have dropped to a new equilibrium and either fat oxidation would ramp up or some other metabolic adaptation would occur (using less energy).

On the high carb diet the glycogen reserves remain topped up by carbohydrate intake and, perhaps surprisingly, the elevated carb intake and consequent insulin levels doesn't suppress fat release to the point where it can't keep up with energy demand.

The study could perhaps be improved by doing a 2 week run-in on the test diet before the 6 days under closer observation. This would make the observed days more representative of a steady state.