Overfeeding and weight loss on oil

Over 40 years ago a paper presented two studies on overfeeding with a high fat diet. I was drawn to read this by wanting to see how it compared with Sam Feltham's experiments and to address the general question about overeating on a low carb diet.

The paper is by German authors - Kasper, Thiel and Ehl - and may have suffered a little in translation as the two separate studies are somewhat intertwined. Well, here goes -

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.

Atkins and 5 / 7 a day

Bit off fuss in the news this morning where a new study (statistical analysis) suggests that 7 a day "portions" of "fruit and veg" is better than the currently recommended 5 a day based on general mortality as well as death from cancer, heart disease and stroke.

In other words if you eat more vegetables and fruit you're less likely to die in a car accident. This may seem flippant but a) it is April 1st and b) that's what they're saying when looking at "all cause mortality"....

Death risk from any cause decreased as fruit and veg consumption increased. Risk of death by any cause was reduced by:

14% by eating one to three portions of fruit or veg per day

29% for three to five

36% for five to seven

42% for seven or more

Fresh vegetables had the strongest protective effect, followed by salad and then fruit.

Fruit juice conferred no benefit, while canned fruit appeared to increase the risk of death - possibly because it is stored in sugary syrup, say the researchers.

Let's not forget that " Potatoes and cassava don't count because they mainly contribute starch to the diet " - not that low carb eaters would be bothering with those things anyway.

So where does this leave the health concious low carb eater ? The good old 42 year old fad that is the Atkins diet usually catches some stick on these occasions, but let's remind ourselves of the facts that in Phase 1, the most restrictive, the current Atkins plan requires 12 to 15 grams of carbohydrate from foundation vegetables.

So is the Atkins diet compatible with 5-a-day or 7-a-day of vegetables (and fruit) ?

According to conventional wisdom dietitians a portion is 80 grams which I think originates from the World Health Organisation. 5 or 7 a day at 80 grams each is 400 to 560 grams a day. If the carbohydrate content is low enough, less than 5 grams per 100 grams of veg, then the limits of Atkins Phase 1 are not incompatible with 5 or even 7 a day :-

	Grams / day of vegetables
Carbohydrate g/day	400	560
12	3.0	2.1
15	3.8	2.7
	Carbs g/100g

[ Note for Americans - UK / EU labelling reports carbohydrates separately to fibre, effectively "net carbs", so these numbers are lower than you are used to. ]

Some example vegetables from Tesco.com :-

	Carbs g/100g
Green beans	3.2
Brussel sprouts	4.1
Cauliflower	3.0
Savoy cabbage	4.1
Spinach	1.6
Kale	1.4
Mushroom	0.4
Romaine lettuce	1.7
Asparagus	2.0
Broccoli	1.8

Clearly it is possible to comply with 5-a-day of vegetables and 7-a-day too if you're careful to pick the right vegetables.  You may be able to add 80 grams of raspberries a day (3.7g of carbs) into your discretionary non-foundation veg carbs too, or as you move into Phase 2 the chocie of vegetables and berries will increase accordingly.

I conclude that the Atkins diet is entirely compatible with the "5 a day" message, in fact it's effectively built in with the 12-15g of carbs from foundation vegetables. Enjoy !


PS Full study behind the headlines is "Fruit and vegetable consumption and all-cause,
cancer and CVD mortality: analysis of Health Survey for England data" by
Oyinlola Oyebode, Vanessa Gordon-Dseagu, Alice Walker, Jennifer S Mindell.
To be found online, currently with Open Access.
JECH Online First, published on March 31, 2014 as 10.1136/jech-2013-203500


PPS You might be interested in an audio podcast about getting overweight children to eat more vegetables (and fruit).

Sugar

A lot of media fluster about sugar this morning, some single issue campaigning group trying to make out that a single substance or group of substances is behind the "obesity epidemic".

I'm sure these underemployed cardiologists have looked at the evidence, but the sugar consumption thing has always intrigued me as I used to make the stuff. In the UK we make / import about 2.5 million tonnes of sugar net of exports and it has been like this for 30 years or more. I must dig out those statistics.

Meanwhile I looked at a UK Govt food survey statistical digest and pulled out the data below :-

I have also been reading a paper from 1995 which observed that ..

The prevalence of clinical obesity in Britain has doubled in the past decade.....  However, average recorded energy intake in Britain has declined substantially as obesity rates have escalated.

So the fans of calorie restriction have a real problem. They can't blame obesity on gluttony, as several datasets and studies show that our calorie intake is declining. So they're left with sloth and assuming that we're all doing 1000 calories a day less activity (yeah, right) to justify the increase in obesity.

Likewise the fructophobic cardiologists, in remission from lipophobia, are going to struggle to explain the effect of declining sugar intake on increasing obesity.

Facts about Carbs

Last week the NHS published an opinion piece opposed to low carbohydrate diets. They didn't even get past the first paragraph before naming and attacking well known diet plans that have helped many lose weight. This is a shame, as we need to use any approach that works if we are to address the obesity issue, and carbohydrate restriction has been demonstrated to work in many studies :-

The above are all Randomised Control Trials, analysed with references at authoritynutrition.com and a similar list is at dietdoctor.com showing a large majority of studies finding higher fat / weight loss in the low carbohydrate group of the trial to be better than in the low fat group.

In the NHS article a single study of the Atkins diet is referenced and it is said that

 "A 2003 study found that a low-carb diet can produce quick results, but over the long term it does no better than a balanced diet featuring carbs."

The full story is a little more complex...

 "Subjects on the low-carbohydrate diet lost significantly more weight than the subjects on the conventional diet at 3 months (P=0.002) and 6 months (P=0.03)"

The weight loss at 12 months was still better in the low carb group, but high attrition rates and some issues with the trial design like mixing men and women reduced them below statistical significance (P=0.26). A picture is worth a thousand statistics :-

The attrition rate itself is also of interest -

"The percentage of subjects who had dropped out of the study at 3, 6, and 12 months was higher in the group following the conventional diet (30, 40, and 43 percent, respectively) than in the group following the low-carbohydrate diet (15, 27, and 39 percent, respectively)"

 so it appeared that the low carbohydrate diet did at least work better for more of its participants in that they were more likely to stick with it. carrying forward baseline data means putting the weight of dropouts at their entry value, which makes both groups look worse than the reality of those who completed the programme.

As we would expect there were improvements to blood lipid composition in the low carb diet of this study, but the NHS omit to mention this. Similar results appear across the studies linked to in the above reviews, and recent systematic reviews confirm the benefit of low carbohydrate eating in terms of reduced cardiovascular risk.

So, a shameful piece of conventional wisdom and anti-low carb thinking is published in a context that requires balance, integrity and accuracy. Those of us hoping for a Damascene conversion on the way to Stockholm are disappointed, and the Swedish review that concluded "too much carbohydrate, not fat, leads to obesity" was clearly a better piece of work than asking "Dietitian Sian" for her opinion.

Here are three facts omitted by the NHS :-

1. There are no essential carbohydrates that we have to eat in order to live. This is not the case for fats and proteins where we do need to take in some of each of them in food as our bodies can't make them.

2. There is no diagnosable disease of carbohydrate intake deficiency. Diabetes on the other hand is a difficulty in processing or controlling carbohydrates which leads to high blood sugar levels with clinical symptoms that can be serious. Excess carbs are stored as body fat once glycogen stores are full.

3. The human body at rest uses fats to provide about 2/3 of its energy requirements, with 1/3 from carbohydrates. At high / strenuous exercise rates the proportion of energy from carbs approaches 100%.

Carbs for energy are taken from food and from glycogen reserves which are limited to a maximum of about 2000 calories (kcal). There is only 5 grams of glucose in your bloodstream (20 calories, about 15 minutes worth at rest). A lean athletic man of 75 kg / 165 lbs / 11 st 11 lbs with 12% body fat has about 70000 calories of fat reserves, ideal for endurance activity or periods of famine.

In the absence of dietary carbohydrates the brain switches to ketones as a fuel and glucose is made by the liver - we are dual fuelled / hybrid powered beings where carbs provide short term power / acceleration and fats provide long term endurance and survival. The NHS articles assertion that we are 100% fuelled by glucose is incorrect. Carbohydrates are a low density fuel - would you rather haul fat at 9 calories per gram or carbs at 4 cal/g over the Antarctic ice sheet or up Everest ?


Have a Happy Christmas !

Fat Fast / Cream Day

Well here I am 3 years down the line, and still eating low carb. My current weight is 11 stone 10 lbs ( 164 lbs or 74.5 kg if you prefer other units ) which is as low as I've ever measured. I must have weighed this as a boy, but boys don't weigh themselves. My BMI is 23 !! Low carb delivers, and I haven't "put it all back on again" as various cynics, refuseniks, dietitians and general tossers on the internet would have you believe.

I dropped 8 lbs recently on a rather good and special holiday, more of which later.

About a month ago I did a sort of "fat fast" to try to boost my weight loss a bit and see if I could increase the ketone levels in my blood - aiming for the "nutritional ketosis" nirvana that people enthuse about on the web. I wrote it up as a document that you can read or download from Google Drive

Dr Atkins described a fat fast in his original book in 1972, used to kick start his diet in some resistant individuals who needed to have very low levels of carbohydrate and protein to cut down their blood sugar levels and get the brain switching over to use ketones from fat as its primary fuel. From memory he aimed at 1000 calories with basically all of them (90%) from fat - macadamia nuts and some cream cheese for example. A fat fast cookbook has been published recently, for those looking for detailed guidance, but I haven't read it yet.

My fat fast delivered a 3 pound weight loss in one day, and ketone levels increased progressively with the overnight fasted result up in the magic "nutritional ketosis" range :-

I think a fair chunk of the weight loss was water associated with glycogen, as the lack of carb intake and the day's activities would have depleted my liver's glycogen reserves and forced the use of glucose and ketones produced by the liver to provide the body's energy requirements (along with fatty acids from my fat stores, of course).

My total food intake for the day was 1480 calories, with 78% from fat and 71 grams of protein, so this was not a real "hard core" fat fast to the letter, but a decent amount of food with controlled protein, low carbohydrate and lots of lovely nutritious fats to scare the cardiologists away.

It's interesting that 40+ years after Atkins wrote his book "Dr. Atkins' Diet Revolution" , and 10 years after his death, people like me can re-discover his ideas and find they are still relevant. They may in fact still be "best practice"  despite all the low fat calorie restriction dogma we have been subjected to since.

Nutritional Guidelines & low carb eating

Let's take a look at UK nutritional guidelines, from the back of a pack of ASDA Mackerel fillets :-

Guideline daily amounts
                          Women                  Men
Calories                   2000                 2500
Protein                     45g                  55g
Carbohydrate               230g                 300g
of which sugars             90g                 120g
Fat                         70g                  95g
of which saturates          20g                  30g
Fibre                       24g                  24g


In the early stages of my low carb diet I was limiting my carbohydrate intake to below 20g per day. This means I was eating 280g less than the guidelines, a saving of 1120 calories per day ! That is enough to drop my calories to 1380 per day if nothing else changes.


1120 calories per day is equivalent to about 124g of fat from my ample deposits, so a loss rate of 124g per day relative to the standard guidelines looked to be on offer. At 871g per week that's 1.9 pounds (lbs) per week and close to 50 lbs or 3.5 stones in 6 months. Perhaps a bit more if you include the water weight that is also stored with the fat on your body.


I did actually lose 3 stones in 6 months, from just over 16 stone in April 2010 to just under 13 stone in October 2010. So the reduction in carbohydrate compared to the standard food guidelines seems to equate to my weight loss, more or less.


In practice I eat more protein than the guidelines, probably 90-100g say 50g more which is 200 calories more. My fat intake is probably around the 95g mark, so my calories are approximately  :-


Carbohydrates   20g    80 calories
Protein        100g   400 calories
Fat             95g   855 calories


Total                1335 calories, 64% of which from fat.


Am I losing out by having a low carbohydrate intake ? Not in my opinion. There are essential minerals and vitamins we have to eat, and essential fatty acids. "Essential" means we have to have it and we can't make our own, so we have to eat it. There are no essential carbohydrates !


Low carb dieters adapt to use fat as a muscle and brain fuel, to replace the glucose that would otherwise be used. The whole blood stream only contains about 5g of glucose so it is continually being used and replaced with glucose from food or from previously stored glycogen. When the supply of glucose isn't enough then fat is broken down and ends up as ketones to fuel muscles and the brain. Some parts of the body can only use glucose, but there's enough for them from conversion of protein ie Gluconeogenesis.


Once adapted to low carb eating my blood sugar became stable, I didn't feel hungry and sugar highs and lows were a thing of the past. My metabolism has adapted to my diet which is no longer based around fast absorbed carbohydrates as recommended in the Guideline Daily Amounts.