Yesterday, my article was about the

Difference between Correlation and Causation.

Below are two examples of media
handling the same recent health research study.

 

 

7 Daily Servings of Fruits, Veggies Best for Happiness,
Study Finds 'Strive for 5' might need an update. 
        Oct. 12 (HealthDay News) 

"People who eat seven servings of fruit and vegetables a day have the highest levels of happiness and mental health, according to a new study.

In a joint effort with Dartmouth University, researchers at the University of Warwick examined the eating habits of 80,000 people in England and found that mental well-being rose with the number of daily servings of fruits and vegetables, peaking at seven servings a day.

The study, which appears in the journal Social Indicators Research, defied a serving as about 80 grams (2.8 ounces).

"The statistical power of fruit and vegetables was a surprise. Diet has traditionally been ignored by well-being researchers," study co-author Sarah Stewart-Brown, a professor of public health, said in a university news release.

Further research is needed to learn more about the reasons behind the findings, she added.

"This study has shown surprising results, and I have decided it is prudent to eat more fruit and vegetables. I am keen to stay cheery," study co-author Andrew Oswald, a professor in the economics department, said in the news release.

Currently, many Western governments recommend that people eat five servings of fruit and vegetables a day to protect against heart disease and cancer, the release noted.

While the study found an association between fruit and vegetable servings and well-being, it did not prove a cause-and-effect relationship."

 

 Here’s another take on the same Research.

Study: If You're 'Keen to Stay Cheery,'
7 Fruits and Vegetables a Day
        By Lindsay Abrams 
        Oct 14, 2012 (the Atlantic)

"On the psychological side of dietary recommendations

PROBLEM: We go on about eating for health, but we're usually talking about the physical side. The World Health Organization recommends five servings of fruits and vegetables a day for your body, but not much is known about how much is best for psychological well-being.

METHODOLOGY: Economists and public health researchers from the University of Warwick, in conjunction with Dartmouth College, used data from several randomized, cross-sectional surveys that accounted for the eating habits of about 80,000 people living in the U.K. The fruits and vegetables typically consumed by each person were compared with their life satisfaction, mental well-being, presence of mental disorders, self-reported health, happiness, nervousness, and how often they "feel low."

They factored in as many variables as they could think of, including other the rest of their diets, alcohol, and lots of demographic, social and economic factors.

RESULTS: A "remarkably robust" pattern was found, in which "happiness and mental health rise in an approximately dose-response way with the number of daily portions of fruit and vegetables." While in some cases it rounds out at the recommended five per day, well-being appears to peak at seven.

In many cases, the improvements associated with fruit and vegetable consumption were substantial. For example, the authors explain that "When comparing small and large levels of fruit and vegetable consumption per day, the effect corresponds to between 0.25 and 0.33 life-satisfaction points. To put that in perspective, the known (huge) effect of being unemployed corresponds to a loss of 0.90 of a life-satisfaction point."

CONCLUSION: The findings are "consistent with the need for high levels of fruit-and-vegetable consumption for mental health and not merely for physical health."

IMPLICATIONS: This isn't a definitive randomized trial, but it's an interesting correlation that warrants more research. Economist Andrew Oswald in the Department of Economics at the University of Warwick seems pretty convinced, though. As he put it, "This study has shown surprising results and I have decided it is prudent to eat more fruit and vegetables. I am keen to stay cheery."

Aren't we all, Professor Oswald. Aren't we all.

The full study, "Is Psychological Well-being Linked to the Consumption of Fruit and Vegetables?" will be published in the journal Social Indicators Research. "

 At the end, both of these articles specifically admit that this study involves only a correlation, not causation.

However, do you join me in thinking that a typical reader of these articles will come away believing that new research says that they would probably be happier if they ate more fruits and veggies? And… that one of the reasons they now feel unhappy, could be because they don’t eat ENOUGH fruits and vegetables?

One of the most common errors in the press is the confusion between correlation and causation in scientific and health-related studies.

In theory, these are easy to distinguish … an action or occurrence can CAUSE another (such as smoking causes lung cancer), or it can CORRELATE with another (such as smoking is correlated with alcoholism). If one action causes another, then they are most certainly correlated.

But just because two things occur together does not mean that one caused the other, even if it seems to make sense.

In general, we should all be wary of our own bias. We like explanations. The media often concludes a causal relationship among correlated observances when causality was not even considered by a research study itself. Without clear and definite reasons to accept that one thing CAUSES another, the fact that a correlation exists is all we should accept. Again, two events occurring in close proximity does not imply that one caused the other, even if it seems to makes perfect sense.

Once upon a time, this type of error wasn’t too bad.
If one ate a berry and got sick, it was wise to see meaning in that data. (Better safe than sorry). The same goes for a red-hot coal. Only one touch will give all the correlations needed. Being bullied by a primitive world of nature, it's far worse to miss a link than it is to make one up. A false negative yields the greatest risk.

Now conditions are reversed.
People in modern civilization are bullies over nature. New claims about causation are often made so we can make large interventions in nature. A false positive today often means approving drugs that have no effect, or imposing regulations that make no difference, or wasting money in schemes to limit unemployment. Now, as science grows more powerful and government more technocratic, the stakes of correlation…. of making counterfeit relationships and bogus findings,… grow larger and larger. A false positive is now more burdensome than it's ever been. The only thing we have to fight this attitude is the catchphrase. “correlation is not causation”.

I suggest that we be very cautious in the way we allow media claims to influence us into making personal changes in our own behaviors, ... especially in relation to the way they tend to limit our personal choices of the foods we eat, and the way they tend to add to our personal expense and health risks through recommendions of unnecessary drugs. 

Mistaking correlation for causation finds a cause that simply isn't there.

                              
Which is better or most effective, cutting Carbs, or cutting Calories?

Everything I’ve seen and experienced personally, leads me to believe that calories matter even when one chooses to eat low-carb. There’s a possibility that one can eat a few more calories by reducing carbs, but … for most people … the amount of extra calories doesn't appear to be a very large number.

 It seems like there are an endless number of specific diets and rules for weight loss. One of the most popular of these rules is that cutting carbohydrates (carbs) is the best way to lose weight.

The Atkins diet, first popular in the 1970s.is the most famous low-carb diet. This diet recommends limiting foods high in carbs, such as bread, pasta, rice, and starchy vegetables such as corn and potatoes. Carbs are replaced with foods containing a higher percentage of proteins and fats (meat, poultry, fish, eggs and cheese) and other low-carb foods (mostly vegetables).

What does the evidence show us about whether low-carb diets really are better for weight loss and weight-maintenance than other diets?

Conventional wisdom says that a “calorie is a calorie” and it doesn't matter what types of food the calories come from, and therefore, all reduced-energy (calorie) diets should lead to equivalent weight loss.

However, some studies have reported that low-carb diets, in the short-term, lead to greater weight loss than other types of diets. What are some possible explanations for these results?

1. Changes in body composition

Energy is stored in the body as protein, fat, and glycogen, which is a form of carbohydrate. If there is an imbalance between how many of these nutrients are ingested (through the food that is eaten) and how many are used by the body for every day functions, body composition will change.

In turn, this will affect body weight because of the different impact that the relative amounts of stored protein, fat and carbohydrates have on body weight.

However, the vast majority of studies in which they’ve measured calorie intake very accurately (that is, they’ve locked people in a room and measured exactly what they’ve eaten for several days), show absolutely no difference in weight loss based on the composition of the diet. High-protein diets and high-carb diets resulted in the same weight loss.

2.  Changes in metabolic rate

The body’s metabolic rate (the amount of energy expended by the body in a given time) is dependent on the composition of the diet. Consumption of protein, for example, is known to result in a larger increase in energy expenditure for several hours after a meal compared with the consumption of fat or carbs.

But the overall effect of diet composition on total energy expenditure is relatively small. As a result, the assumption that a “calorie is a calorie” is probably a reasonable estimation as far as energy expenditure is concerned.

3.  Changes in hunger levels and satiety

Some diets can lead to reduced hunger, improved satiety (feeling full), and can be easier to stick to than others. There is an enormous amount of research on this.

The problem is that it’s extremely difficult to accurately measure what people are eating over extended time periods. In general, people rarely stick to their diets for more than just a few weeks, making it almost impossible to adequately compare the effects of different diets.

And so, is cutting carbs the best way to lose weight?  Maybe.

However, all diets with similar calorie content appear to have a similar effect on weight loss in the long-term. This is probably because the body adapts rapidly to changes in relative protein, fat and carbohydrate intake levels.

The truth is that losing weight and keeping it off in the long-term is difficult. It requires permanent changes to the number of calories you eat each day. My own maintenance struggle has involved experimenting with many different diets, or ways of eating.

  I believe the best diet for a person, is whatever diet that person is able to live with comfortably long-term. My own maintenance involves a continual process of looking for a way of eating that satisfies that criteria for me, personally.  As a part of that process, I’ve made Dieting into a rather enjoyable Hobby for myself, which is why this website is named DietHobby.

                             

Although almost every weight-loss expert seems to have something to sell,
...... despite the marketing hype ,...... there are kernals of truth in many of the basic things they say.
 

"Science has failed us in the weight loss department.
It literally gets an “F.”

The culture has failed us as well. Far too many people have intense moral judgments towards anyone with excess pounds, which contributes to the hidden epidemic of social disconnection, apathy, and plain old sadness.

Let’s face it: when it comes to the subject of weight gain and weight loss, we’re clueless.  And from that place of cluelessness we tend to flail around, we try our hand at the most inane weight loss strategies, we diet for decades, we consume diet foods ...that are, if you care to closely study the scientific literature ... toxic."

                    Marc David - Psychology of Eating

                             
It's hard not to binge on delicious food. For more about that experience, go to the bottom of the page, and Watch an entertaining video at the end of this article.

However, that is NOT the ONLY reason why weight-loss is hard.  I've been reading about "Adaptive Thermogenesis" .  Physical systems (like machines) stay the same.  Biological systems (like humans) adapt.

Weight-loss and maintenance have less to do with motivation and will-power than most people think. In fact it has far more to do with how your body adjusts to, and is capable of, resisting a calorie deficit. Putting less fuel in the tank of one's car will always cause the car to drive a shorter distance.  However, the human body adapts to less fuel ....meaning eating fewer calories.... by becoming more ‘efficient’ and running the same distance on less fuel than before. That is the big difference between simple physics and biology

For a better understanding of the issue of energy-in/energy-out, read my Summaries of what Gary Taubes has to say about it. 
WWGF - Chapter 6 Thermodynamics for Dummies, Part 1
and Chapter 7 Thermodynamics for Dummies, Part 2.

Here is a great article by Dr. Arya Sharma M.D. on this issue:

The Role of Adaptive Thermogenesis in Resistance to Weight Loss

No intentional weight loser continues to lose weight till she disappears.

Sooner or later every diet, every medication, or every type of bariatric surgery will result in a weight loss ‘plateau’ (better referred to as a ‘floor’) - a weight, beyond which losing even more weight (and keeping it off) becomes an almost ’super-human’ feat.

However, there is considerable variation in how much weight people can lose and keep off. Although the average sustainable weight loss with ‘eat-less-move-more’ (ELMM) approaches is about 3-5% of initial weight, some folks manage to lose considerably more, while others struggle to even simply stop gaining weight.

This has less to do with motivation or will-power than most people think.
In fact, it has far more to do with how your body adjusts to and is capable of resisting a calorie deficit.

While putting less fuel in the tank of your car will consistently decrease the distance that you can drive, our bodies adapt to less fuel (i.e. eating fewer calories) by becoming more ‘efficient’ and running the same distance on less fuel than before. That is the big difference between simple physics and biology.

Biological systems adapt - physical systems (like your car) stay the same.

In the case of humans (and animals) we call the adaptation of energy needs and expenditure ‘adaptive thermogenesis’. Exactly how adaptive thermogenesis is regulated and how differences therein can largely determine both weight loss and weight regain, is the topic of a paper by Angelo Tremblay and colleagues from the Universities of Laval and Ottawa, published in the International Journal of Obesity.

As the authors point out,

“The decrease in energy expenditure that occurs during weight loss is a process that attenuates over time the impact of a restrictive diet on energy balance up to a point beyond which no further weight loss seems to be possible. For some health professionals, such a diminished energy expenditure is the normal consequence of a progressive decrease in the motivation to exercise over the course of a weight-reducing program.”

Many studies have now documented the process of ‘adaptive thermogenesis’, whereby weight loss is associated with a ‘greater-than-predicted’ decrease in energy expenditure. This occurs both through a reduction in metabolic rate as well as through an often remarkable increase in ‘fuel efficiency’ related to physical activity, whereby individuals, who have lost weight burn far fewer calories for the same amount of physical activity than before losing their weight (far more than can be explained simply by considering that they are also moving less weight around).

As the authors discuss, not only do people, who demonstrate the greatest decrease in adaptive thermogenesis in response to weight loss tend to lose less weight (for the same level of caloric restriction) but they also tend to have a greater increase in hunger and appetite.

Also, it does not appear that these ‘adaptive’ responses to weight loss diminish over time, which means that the resistance to further weight loss and the propensity to weight regain persist till the weight is eventually regained (i.e. they once again ‘fail’).

Together, these factors can easily explain why losing weight and keeping it off is far more difficult for some folks than for others - irrespective of motivation or will power.This basic biological fact is not only important to ‘dieters’ (even if it seems demotivating) - but perhaps even more important for all health professionals to be aware of.

Simply ‘blaming’ people who find it harder to lose weight or keep it off for their lack of will power or motivation, is neither fair nor helpful. You can only fight your biology so far before life is no longer fun - this is when you need to realize that you are now living below your ‘Best Weight’.

AMS
Edmonton, Alberta

Tremblay A, Royer MM, Chaput JP, & Doucet E (2012). Adaptive thermogenesis can make a difference in the ability of obese individuals to lose body weight. International journal of obesity (2005) PMID: 22846776

Dr Arya Sharma, M.D. 
Dr. Sharma’s Obesity Notes   www.drsharma.ca