Wednesday, February 13, 2008

Diet drinks are fattening

Consuming low-calorie drinks may increase the risk of putting on weight, according to scientists in the United States. They have suggested that people who choose diet drinks containing artificial sweeteners tend to overcompensate and consume more calories than those who do not.

Although the rise in obesity has corresponded with a growth in low-calorie soft drinks, designed to make keeping weight down easy by replacing sugar with saccharine or other sweeteners, scientists who conducted experiments using rats at Purdue University, in Indiana, have suggested that the opposite may be happening. They found that rats fed on yoghurt sweetened with saccharine ate more calories, gained more weight and put on more body fat than rats that were given yoghurt sweetened with glucose.

Susan Swithers and Terry Davidson, who conducted the experiments, have suggested that, by breaking the connection between a sweet sensation and high-calorie food, the use of saccharine changes the body's ability to regulate how many calories it consumes. "The data clearly indicate that consuming a food sweetened with no-calorie saccharine can lead to greater body-weight gain and adiposity than would consuming the same food sweetened with a higher-calorie sugar," they conclude in their report, which is published in the journal Behavioural Neuroscience.

They admit that their results may seem counterintuitive and might not be welcome to nutritionists and doctors who have long recommended low-calorie or no-calorie sweeteners. But they say that their findings match emerging evidence that people who drink more diet drinks are at higher risk of obesity and metabolic syndrome, a collection of medical problems such as abdominal fat, high blood pressure and insulin resistance that put people at greater risk of heart disease and diabetes.

People and animals learn that eating certain foods has consequences. Sweet tastes signal calories. If that link is broken, the researchers suggest, then the individual loses the ability to judge how many calories are being consumed. One controversial theory is that calorie consumption is signalled by a rise in body temperature after eating. The greater the rise in body temperature, the more aware the individual is that a lot of calories have been consumed.

In the experiments the rats that were used to eating low-calorie yoghurt showed a smaller rise in temperature after eating a different, calorie-loaded meal. It appeared that their ability to detect calories had been blunted, leading to overeating.

Normally, the researchers say, sweet foods provide a stimulus that strongly predicts that someone is about to take in a lot of calories and their ingestive and digestive reflexes gear up for that intake. But when false sweetness is not followed by lots of calories the system gets confused. Thus, they argue, people on low-calorie diets may eat more - or expend less energy - than they otherwise would. If their theory is correct, then artificial sweeteners such as aspartame, sucralose and acesulfame K, which taste sweet but do not provide calories, could have similar effects.

The results did not surprise Richard Cottrell of the Sugar Bureau. He said that there had been a number of studies that suggested a link between use of low-calorie sweeteners and weight gain and that dietary studies in humans "do not support the idea that avoiding sugar is a predictor of low body mass index, quite the contrary".

Dr Cottrell said that the evidence suggested that people who chose low-calorie drinks tended to consume more calories. "The advocates of low-calorie products tend to rely on evidence from covert substitution experiments, where the subjects don't know their food has been doctored. But even these experiments suggest that compensation kicks in slowly over a few days. People who know they are `banking some goodness' by taking, say diet drinks, are inclined to overindulge."


Risk-averse world demands the unattainable

Comment on the latest extension of British bureaucracy. New drugs are to be suicide-rated

For drug manufacturers, the hurdles constantly get higher. Patients demand drugs that work effectively but which are targeted so precisely that they have no side-effects. The pharmaceutical industry would like us to believe that such products are possible, but there is hardly a drug on pharmacists' shelves that does not have at least one undesirable side-effect.

Some of the cosiest and most familiar drugs are among the worst offenders. Take aspirin. We all do. This centenarian is a genuine lifesaver, with a near-miraculous list of battle honours. It is effective against pain, but more aspirins are swallowed to protect against heart disease than headaches. Worldwide, more than 60 billion doses are taken every year. Yet if it were invented today, aspirin could never be marketed. Its most dangerous side-effect is damage to the stomach lining, causing ulcers and bleeding. In under16s, it can trigger a rare but potentially fatal condition, Reye's syndrome.

No drug with two such damaging side-effects would get far in today's risk-averse world. Yet it is impossible to deny that, overall, aspirin has done far more good than harm. By expecting drugs to be completely safe we are throwing away potentially valuable products too readily. Whenever new safety rules are introduced, costs rise and it becomes less and less profitable to produce drugs that have a limited market.

So people with rare diseases suffer. "Orphan drug" designations, whereby companies are given incentives to develop less profitable drugs, may help a little but the cost pressures inevitably drive companies to seek big-market drugs, the only way they can get their money back.

The problem then is that a rare side-effect may loom large simply because of the huge number of people taking the medication. It looks awful if thousands of people suffer side-effects and join in class actions, but if tens of millions are taking the drug the numbers suffering may be only one in a thousand or less. The other 999 are alleviating their symptoms and enjoying life.

Side-effects of drugs for treating depression are especially tricky to assess. There is evidence that they may increase suicidal thoughts, if not actual suicide, among adolescents. This may mean that teenagers plunged into gloom are lifted sufficiently by the medicine so that they see the possibility of controlling their lives once more. Thinking of suicide could be a sign of improvement.

If every drug is to be assessed for suicidal thoughts, it creates another barrier, another set of costs, and another reason for rejecting promising medicines because of a side-effect that may be tiny when compared with potential benefits.

The reductio ad absurdum of the search for complete safety is stasis. No new drug will ever be approved because fear has paralysed innovation. Everybody will lose. There will be no new medications, and we will be forced to fall back on those approved in earlier times when standards were lower. So by seeking perfect safety we will end up with drugs that are actually less safe, but familiar. It's enough to give you a headache. I'd recommend an aspirin.



Just some problems with the "Obesity" war:

1). It tries to impose behavior change on everybody -- when most of those targeted are not obese and hence have no reason to change their behaviour. It is a form of punishing the innocent and the guilty alike. (It is also typical of Leftist thinking: Scorning the individual and capable of dealing with large groups only).

2). The longevity research all leads to the conclusion that it is people of MIDDLING weight who live longest -- not slim people. So the "epidemic" of obesity is in fact largely an "epidemic" of living longer.

3). It is total calorie intake that makes you fat -- not where you get your calories. Policies that attack only the source of the calories (e.g. "junk food") without addressing total calorie intake are hence pissing into the wind. People involuntarily deprived of their preferred calorie intake from one source are highly likely to seek and find their calories elsewhere.

4). So-called junk food is perfectly nutritious. A big Mac meal comprises meat, bread, salad and potatoes -- which is a mainstream Western diet. If that is bad then we are all in big trouble.

5). Food warriors demonize salt and fat. But we need a daily salt intake to counter salt-loss through perspiration and the research shows that people on salt-restricted diets die SOONER. And Eskimos eat huge amounts of fat with no apparent ill-effects. And the average home-cooked roast dinner has LOTS of fat. Will we ban roast dinners?

6). The foods restricted are often no more calorific than those permitted -- such as milk and fruit-juice drinks.

7). Tendency to weight is mostly genetic and is therefore not readily susceptible to voluntary behaviour change.

8). And when are we going to ban cheese? Cheese is a concentrated calorie bomb and has lots of that wicked animal fat in it too. Wouldn't we all be better off without it? And what about butter and margarine? They are just about pure fat. Surely they should be treated as contraband in kids' lunchboxes! [/sarcasm].

9). And how odd it is that we never hear of the huge American study which showed that women who eat lots of veggies have an INCREASED risk of stomach cancer? So the official recommendation to eat five lots of veggies every day might just be creating lots of cancer for the future! It's as plausible (i.e. not very) as all the other dietary "wisdom" we read about fat etc.

10). And will "this generation of Western children be the first in history to lead shorter lives than their parents did"? This is another anti-fat scare that emanates from a much-cited editorial in a prominent medical journal that said so. Yet this editorial offered no statistical basis for its opinion -- an opinion that flies directly in the face of the available evidence.

Even statistical correlations far stronger than anything found in medical research may disappear if more data is used. A remarkable example from Sociology:
"The modern literature on hate crimes began with a remarkable 1933 book by Arthur Raper titled The Tragedy of Lynching. Raper assembled data on the number of lynchings each year in the South and on the price of an acre's yield of cotton. He calculated the correlation coefficient between the two series at -0.532. In other words, when the economy was doing well, the number of lynchings was lower.... In 2001, Donald Green, Laurence McFalls, and Jennifer Smith published a paper that demolished the alleged connection between economic conditions and lynchings in Raper's data. Raper had the misfortune of stopping his analysis in 1929. After the Great Depression hit, the price of cotton plummeted and economic conditions deteriorated, yet lynchings continued to fall. The correlation disappeared altogether when more years of data were added."
So we must be sure to base our conclusions on ALL the data. But in medical research, data selectivity and the "overlooking" of discordant research findings is epidemic.

"What we should be doing is monitoring children from birth so we can detect any deviations from the norm at an early stage and action can be taken". Who said that? Joe Stalin? Adolf Hitler? Orwell's "Big Brother"? The Spanish Inquisition? Generalissimo Francisco Franco Bahamonde? None of those. It was Dr Colin Waine, chairman of Britain's National Obesity Forum. What a fine fellow!


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