1 April 2009

News Briefs

Is it finally the end of fad diet wars?
It’s not the type of diet that makes a difference it’s cutting back on the calories that counts. This is the principal finding of a study in the prestigious New England Journal of Medicine that compared four heart-healthy, weight-loss diets. Consisting of similar foods, the diets replaced saturated with unsaturated fat and were high in whole cereal grains, fruits and vegetables. All participants were encouraged to include at least 20 g of dietary fibre per day in their diet and low GI carb-rich foods were recommended.

All four diets were equally successful in promoting clinically meaningful weight loss and the maintenance of weight loss over the course of 2 years. The take-home message is that giving people who want to lose weight a reduced calorie diet that's specifically tailored to fit in with their personal and cultural food preferences is likely to be the best way to give them a real chance for long-term success.

The researchers randomly assigned 811 overweight adults who were very keen to lose weight to one of four diets with a 750 calorie reduction a day that emphasised different amounts of carbohydrates, fat, and protein. The participants were also asked to do 90 minutes of moderate exercise a week. ‘Among the 80% of participants who completed the trial, the average weight loss was 4 kg (8.8 lbs); 14 to 15% of the participants had a reduction of at least 10% of their initial body weight.’ All the diets reduced risk factors for cardiovascular disease and diabetes.

Prof Frank Sacks

The study also showed that the participants who regularly attended counselling sessions lost more weight than those who didn’t. Lead author Prof. Frank Sacks said: ‘These findings suggest that continued contact with the participants may be more important than the micronutrient composition of their diets.’

The good news: If you want to lose weight, see a registered dietitian.
The bad news: It's unlikely that such science-based evidence from Harvard researchers will stop the flow of fad diet books, magazine stories or miracle weight-loss programs, pills and potions.

Helping kids beat the obesity gene
‘Although our genetic make-up does have an influence on our health, it’s certainly not the only defining factor. Those with high risk genes can, in some cases, resist their genetic lot if they alter their lifestyle in the right way – in this case, their diet,’ says lead author Dr Laura Johnson from University College London (UCL) talking about a new study published in March 2009 issue of the online journal PloS One.

Dr Laura Johnson

Children who carry the FTO gene, strongly associated with obesity, could offset its effect by eating a low energy density diet. The UCL and University of Bristol researchers found that children with a more energy dense diet (more calories per bite) tended to have more fat mass three years later and also confirmed that those carrying the high risk gene had greater fat mass overall.

When the researchers looked at whether children with the FTO gene had a stronger reaction to an energy dense diet than children with a lower genetic risk they found that they did not. These results indicate that if a child with a high genetic risk eats a diet with fewer calories per bite, they may be able to offset the effect of the gene on weight gain and so stay a healthy weight.

Eating a diet rich in energy-dense foods increases the risk of obesity for adults, as they tend to eat the same amount of food, regardless of its energy density. That’s not true for kids, Johnson notes. When younger kids eat energy-dense foods, they generally eat less at the next meal. As they get older, though, they get more and more like adults. ‘This is an important finding because it provides evidence that … adopting a diet with more bulk and less energy per bite could help people avoid becoming obese regardless of their genetic risk. Obesity is not inevitable if your genes give you a higher risk because if you change the types of foods you eat this will help curb excessive weight gain.’

How? By replacing high-fat foods with low-fat foods and giving kids more fruits and vegetables. See January 2009 GI News for more on low energy density ‘feel full’ foods and February 2009 GI News for tips on ‘Changing the way we eat, drink and move.’

Carbohydrate withdrawal: is recognition the first step to recovery?
In February 2009 GI News, we reported on an article that explored the idea in that addiction could be an important factor causing the obesity epidemic. Lead writer Dr Simon Thornley claimed that although there’s no basis for this in the medical literature to date, it’s possible that obese persons may experience a withdrawal syndrome (after abstinence from high GI foods) with symptoms such as craving and low mood similar to those associated with other drug dependencies. In a recent letter to the NZ Medical Journal, Thornley reprints correspondence (with permission) from a 38-year-old woman from Wisconsin, USA.


“For the first 3 weeks I cut all processed sugar and flour from my diet and suffered mood swings with extreme tension and depression, even a sense of hopelessness at times, I had horrible stomach pains, all my joints and muscles throbbed, and I had the shakes constantly. I don't even know how to describe the horrible headaches that went along with all this. People who knew me started thinking I was hiding a drug problem. The worst physical symptoms have been gone for about 2 weeks now, and the cravings are finally starting to subside … I look at birthday cake today and all I see is myself curled up in the fetal position crying in bed … The worst part of the addiction lasted 3 weeks. The first 3 days were normal, but then on the fourth day the worst cravings began. All I could think about was ice cream, chocolate, and cheesecake. The cravings started to subside after the third week, but once I started feeling better I [thought] about food less. The shakes and the headaches really were the worst part!”

Thornley says: ‘Although this case does not prove our hypothesis, it may explain why obese people find it difficult to adhere to advice to reduce intake of refined carbohydrates. Her description is similar to an opiate withdrawal syndrome (craving, aches and pains and muscular spasm or twitching). The time course – worst in the first weeks and resolving with continued abstinence within 4 weeks – again concurs with a withdrawal syndrome. Further work may indicate if these symptoms can be reliably measured and mapped over time in obese subjects that limit their intake of high GI food.’


Anonymous said...

Wow! I'm glad I read this. I think it will help me. Thanks.

ALD said...

I think there is somethimg to the carb addition theory. When I cut out sugar and High GI carbs a few years ago I felt like I was going through withdrawal. The sugar cravings were really bad for the first 2-3 days and I had headaches on and off during that time. Once this was over I felt fine but then found things switched and I began to feel unwell any time I had a large amount of sugar.

RickH said...

The dietary study is very misleading - the popular press miss-states that it doesn't matter what you eat, just how much.
Not true, the study had a strong emphasis for high fiber, low GI foods.
The study results really state, on a high fiber, low GI diet, the amount you eat affects how much you lose.
Not very interesting, especially considering that its been misinterpreted to mean, eat anything, including high GI foods.
Any low GI, high fiber diet will result in eating less and losing weight, if you don't overeat and get at least some exercise.

Rohan said...

I have had great difficulties managing my blood sugar and insulin levels since my mid teens, being easily prone to what I assume are episodes of low blood sugar. After I became educated about such conditions and what to do about them, I switched to a no-sugar, low GI diet and have never looked back. However, I will never forget the first two weeks after I gave up the sugar and all high-GI foods. I felt like death itself, plagued by low energy levels, irritability and spectacular headaches. It was truly awful but well worth it in the end. I have little doubt that could be likened to withdrawing from a powerfully addictive drug.

Tholzel said...

It is clear that calories is the ONLY thing that counts as far as weight loss is concerned. What time of calories you eat helps in other aspects of health. But Carb-lust is a real problem--perhaps the major problem of all dieters. So I recommend the Velocity diet (http://www.velocitypress.com/if_atkins_doesnt_work.shtml) which eschews all numbers and merely tells you to cut your current white carbs in half. "Perfection is the enemy of the good."
Trying to radically cut all bad carbs is self-defeating, even though it results in quick weight loss, only to crumble as you are overcome by carb-lust. By maintaining the one diet you know you can keep--the one you're on now, whatever it is--and only cutting back a resonable amount on white carbs, you can avoide dreaded carb-lust and slowly chisel back on overall calories.

Anonymous said...

I firmly believe that there is such a thing as carb addiction. It is great to read this article to reinforce what I concluded based on my own feelings. As I continue to purchase and ingest massive amounts of refined carbohydrates I wondered with despair why I felt hopeless and helpless to control myself. I am an educated individual with mass amounts of knowledge on nutrition and moderately overweight (20-30 pounds). However, I could not control myself in the midst of refined carbs. There is no amount that is enough. I could only conclude my loss of control to be an addiction. This is also supported by how I feel when I consume these carb laden foods. I feel pathetic as I have a piece of cake or candy and feel a sense of euphoria. I hope one day I can find a way to overcome this addiction. For someone who has never felt these feelings it probably sounds ridiculous that is why I never discuss it even with my closest friends or family members. Just typing this response has been very cathartic. I have even contemplated counseling. Is that crazy or what?

RickH said...

Food calories are still mythical--as reliable as using phlogiston...
There are no reliable, accurate studies relating food calories to reality--they are a marketing tool.
A real study would have a group of people eating the same quantity of the same food and measuring their blood sugar change, like in a GI rating--never been done, because the data would utterly contradict the existing food calorie tables based on measuring energy released by burning food, not by the body digesting food.

GI Group said...

Hi Rick, Using existing food tables, researchers have been able to keep people in weight balance over weeks and months. They have also been able to predict the rate of weight loss when a calorie deficit is planned (and weight gain when that's been the goal). Nothing's perfect but they are not 'mythical'.

RickH said...

Food calories are not scientific, nor based on science, and are totally misleading. Yeah, you can use them to lose weight, but you can end up starving yourself and losing less weight than if you followed a low GI diet.
You can actually eat a high calorie, low GI diet and lose tons of weight. Not great for you, but shows how misleading using calories can be.
You can also eat a low calorie, high GI diet and not lose much weight at all.
Food calories should not be used, unless you are trying to trick ignorant people.
Until food calorie tables are based on lab results using real people to measure the energy, they are mythical, not science.

hermin said...

@ Rick: I believe that all dietary rules are not meant to be used in isolation. That's why relying on calorie counting alone can be misleading, as you said. Satiety and nutritional balance (plus food preferences!) are a very important factors - these are where the Low GI diet comes in.

BUT this doesn't mean that food calorie tables are mythical or non-scientific. They ARE scientific. One gram of fat produces about 9 calories - that's certain. Having said that though, we shouldn't use "calorie contents" as the ONLY criterion to determine which food to eat".

@ anonymous: i think that makes sense. Sugar does cause some kind of "addiction" (because it increases the level of serotonin).

Hope these all make sense :)

GI Group said...

Thanks for your comments Hermin. We are planning a story on calories down the track (much later this year) as scientists are researching this area.

RickH said...

How is that measured? One gram of fat produces 9 calories by burning in a calorimeter? Or by producing energy in a N European person with an efficient fat processing metabolism? Or someone who whose metabolism doesn't use fat efficiently.
That's where the science breaks down. The calorimeter is accurate and scientific, but it does NOT measure food calories. Gasoline, wood chips, and fuel oil all can have their physical calories accurately measured by this method. But none of them are food calories. Try and look up the conversion factors for physical calories to food calories, and the basis for their value. Very little scientific work here, mostly inaccurate guesses.

hermin said...

@ Rick: Yes, laboratory studies (e.g. bomb calorimeter) cannot mimic our body's physiological metabolism. But:

1. Nutrition scientists use a more precise method (using humans in a controlled condition) rather than just burning fat inside a calorimeter filled with water.

2. Even though everyone's metabolism is not the same, the foods with greater calorie content will always produce more energy (or increase more weight). 10 g fat would always produce more calories than 10 g carbs, regardless of the person's metabolism, regardless of their age, their muscle.

RickH said...

Absolutely goes against all practical and experienced weight loss that I have experienced --and goes against the GI model.
I have gone on a high fat/protein/fiber diet very high in calories and lost far more weight than I did on a high carb diet that is far lower in calories.
All you need to watch is glycemic index and load. Calories are meaningless in a GI world, and are very misleading.
Grain alcohol, GI of 0, is rated very high in food calories. You will gain 0 fat drinking grain alcohol. You would starve to death trying to get enough energy from alcohol to live.
Eating too much fat is not heart healthy, but has very little to do with gaining or losing human body fat. Human body fat is created by insulin in response to high blood sugar; no high blood sugar, no insulin, no fat.
I have looked for results similar to the GI testing labs rigorous documented tests, for calories. They don't exist.

hermin said...

@ Rick: I'm glad you are very positive about the low GI diet. The great thing about the low GI diet is: it is simple, achievable, flexible and also based on good science. (They are backed up straight from the nutritionists!) It allows us to eat our favourite foods too. Besides, this diet goes in line with our healthy eating principles, so it is not confusing for us.

hermin said...

"Eating too much fat is not heart healthy, but has very little to do with gaining or losing human body fat. Human body fat is created by insulin in response to high blood sugar; no high blood sugar, no insulin, no fat."

My comment: Three years ago I ate a lot of cheese (which is rich in fat) and spread peanut butter thickly on my low GI bread. As a result, I put on a lot of weight (a whopping 8 kgs!) Luckily I was able to lose all those weight (plus extra more kilos off) because I have cut down my fat intake (while keep on eating low GI foods) and moved more.

GI Group said...

Hi Hermin, Just like to say we always enjoy your contributions to this blog. It's good to see you back.

RickH said...

Human fat is created by insulin by turning excess blood sugar to human fat. Foods with very low or 0 GI don't produce much or any insulin response, so can't produce human fat. So saying that you gain human fat by eating dietary fat is absolutely wrong. Show me the biochemical mechanism by which this can happen.
Food calories don't have to be mythical --testing can be done on humans that accurately relate actual energy gained by eating food. The results would be controversial, though. High GI foods would show as having lots of food calories. Alcohol, fats, and oils, would show as having much, much lower food calories, breaking the current calorie tables.
Physical calories measured in a calorimeter are not food calories. Determining the relationship between the two based on repeatable tests using humans is the real issue --that hasn't been done, or if it has, the results not released to the public.
Atkins diet shows that 0 carb moderately high calorie diets can result in high weight loss, it depends on the person.

hermin said...

Thanks GI Group :-)

Rick: You might want to search the Google Scholar to find this article: (free of charge)

Mechanism of Free Fatty Acid–induced Insulin Resistance in Humans
(by Michael Roden et al) - Journal of Clinical Investigation 1996.

So fatty acids DO induce insulin response and increase insulin resistance. Secondly, all excess calories will be stored as fat. If not, how will it go out of the body? Urine should not contain glucose or ketone bodies (if that happens, this means that your kidney is not working well)

Re your comment: "Atkins diet shows that 0 carb moderately high calorie diets can result in high weight loss, it depends on the person."

--> Weight loss from this diet comes from muscle breakdown and water. At the same time, the metabolism rate plummets. The person will be very delighted "Yay, I've lost weight!" and go back to their usual eating habit. With the low metabolism rate, they usually put a lot of weight back on (even more than they lost).

RickH said...

Atkins diet does cause weight loss by water, most of which is during the first several days. After that, it is minimal. As far as muscle loss, that also occurs but to a very small extent. I exercised and bulked up muscle during my experiments with Atkins.
Read up on ketosis, which is the main source of energy for someone on an Atkins diet.
As far as the article on fats causing an insulin response, that is misleading. The amount is so low, that very little if any human fat is created.
You obviously don't understand the glycemic index, what it measures, and what it means.
You cannot show a reliable relationship between food calories and the glycemic index except generally that high carb/high GI foods have high food calories.
It normally takes a significant spike in blood sugar to produce enough insulin response to produce human fat.
The glycemic index was created to show this relationship; the lower the GI, the lower the insulin response. If you don't believe this, why are you posting on a GI Website?