jamba juice

More on Diet Drinks: Best Studies Show They Aid Weight Loss

Sugar in Processed Foods

Sugar in Processed Foods – UCSF

One theme we’re going to return to over and over here is the bad science we see in media every day. Media needs content, so even bad studies with no control groups and self-reporting are trumpeted as news, which is one reason why we are assaulted by supposed proof of a diet or health question one day, then fed “proof” of the opposite the next. It’s all to keep you clicking and getting views to pay for the news site; the study promoters want the world to think their results are meaningful so they’ll get funding to do more. Incentives to hype are great, and so hype is what we get.

You can learn to read the studies for yourself to understand which to pay attention to. Or you can read specialty publications that have a record of understanding how real science works so you can rely on them when they say a study’s conclusions are really valid. That’s what I’m trying to do here — I read all the press releases so you don’t have to.

Today’s example is a large meta-analysis by Paige Miller and Vanessa Perez of the Center for Epidemiology, Biostatistics, and Computational Biology, Exponent Inc., published in The American Journal of Clinical Nutrition. A meta-analysis is a statistical study of a basket of other studies which attempts to discern a better answer to questions raised than the individual studies by combining them; techniques for doing this are complex, but the usual result is to quantify a trend in answers over a much larger examined population. The abstract [with my annotations]:

Background: Replacement of caloric sweeteners with lower- or no-calorie alternatives may facilitate weight loss or weight maintenance by helping to reduce energy intake; however, past research examining low-calorie sweeteners (LCSs) and body weight has produced mixed results. [They will go on to show only unreliable studies show diet drinks induce weight gain.]

Objective: The objective was to systematically review and quantitatively evaluate randomized controlled trials (RCTs) and prospective cohort studies, separately, that examined the relation between LCSs and body weight and composition. [A prospective cohort study identifies a sample, characterizes each element of the sample typically by measuring or questioning, then follows the sample to try to show what initial conditions lead to what outcomes.]

Design: A systematic literature search identified 15 RCTs and 9 prospective cohort studies that examined LCSs from foods or beverages or LCSs consumed as tabletop sweeteners. Meta-analyses generated weighted mean differences in body weight and composition values between the LCS and control groups among RCTs and weighted mean correlations for LCS intake and these parameters among prospective cohort studies.

Results: In RCTs, LCSs modestly but significantly reduced all outcomes examined, including body weight (−0.80 kg; 95% CI: −1.17, −0.43), body mass index [BMI (in kg/m2): −0.24; 95% CI: −0.41, −0.07], fat mass (−1.10 kg; 95% CI: −1.77, −0.44), and waist circumference (−0.83 cm; 95% CI: −1.29, −0.37). Among prospective cohort studies, LCS intake was not associated with body weight or fat mass, but was significantly associated with slightly higher BMI (0.03; 95% CI: 0.01, 0.06). [Emphasis mine: only the unscientific prospective cohort studies showed weight gain for diet drink consumers.]

Conclusions: The current meta-analysis provides a rigorous evaluation of the scientific evidence on LCSs and body weight and composition. Findings from observational studies showed no association between LCS intake and body weight or fat mass and a small positive association with BMI; however, data from RCTs, which provide the highest quality of evidence for examining the potentially causal effects of LCS intake, indicate that substituting LCS options for their regular-calorie versions results in a modest weight loss and may be a useful dietary tool to improve compliance with weight loss or weight maintenance plans.

So what we can see here is that self-promoters who wanted to show low-calorie sweeteners had negative effects on body weight and metabolism were citing poor, uncontrolled studies. They explained this supposed effect by claiming these sweeteners confused metabolism by triggering insulin release through their effect on taste buds, but there was no evidence of that. One plausible explanation for the studies showing weight increases for those who reported drinking diet sodas is that such people are already aware of their tendency toward weight gain, and are more likely to consume diet drinks as a result; other factors about them create the weight gain, and their knowledge of their propensity to gain weight is the cause for their choosing to drink diet sodas. Those other causes of weight gain continue during the study, so naturally this population gains more weight than the unconcerned.

Our meta-takeaway from the meta-analysis: correlation is not causation. If you personally want to change some practice or undergo a procedure to improve something about yourself, pay very little attention to studies which are not randomized, controlled trials or their equivalent. Another good example of this is the constant drumbeat of Conventional Wisdom claiming that going to college increases your future earnings; the figures cited are almost always ignoring the fact that people who complete college have thereby been screened for aptitude for admission and then screened again for the ability to stick to a plan. If you are trying to decide whether or not to go to college, your aptitude and fortitude are already determined, and the effect of going vs. not going for you is much less, especially when you evaluate the opportunity costs: what you could be doing instead of college to educate yourself and grow your earnings capacity. Some people (and you might be one of them) would earn more by starting their own business or going to a high tech startup and skipping higher education. Not that earnings are the most important thing; one common pattern is to gain admission to a prestigious school with excellent networking connections and use those ties to jump into a business without bothering to finish school (the route of Bill Gates and many other entrepreneurs.)

Learn to recognize the lies and distortions in the Conventional Wisdom, and chart your own course.

Now it’s likely true that simply drinking water or tea instead of any soft drink is the healthiest option. But for those who appreciate the carbonation and sweet taste of a diet soda, you should feel free to indulge, in moderation. Diet sodas are far better for your body than sugared sodas, large servings of fruit juice, or jazzy Starbucks or Jamba Juice concoctions.

For more on this topic:

Sugared Soft Drinks: Health Risk? (and What About Diet Soda?)
Another Study on Diet Drinks
Fructose: The True Villain?
More on “Fed Up”, Sugar Subsidies, and Obesity

More on science-based diet for health and fat loss:

Getting to Less Than 10% Body Fat Like the Models – Ask Me How!
Starbucks, Jamba Juice Make You Fat
Fat Doesn’t Make You Fat. Government Guidelines Did!
‘Fed Up’ Asks, Are All Calories Equal?
LeBron James Cut Carbs for Lean Look
Why We’re Fat: In-Depth Studies Under Way
Almonds: Superfood, Eat Them Daily for Heart Health
Fish Oil Supplements Ward Off Dementia
Vani Hari: “Food Babe” and Quack
Cleanses and Detox Diets: Quackery
Sugared Soft Drinks: Health Risk? (and What About Diet Soda?)
Gluten-Free Diets: The Nocebo Effect
Acidic Soft Drinks and Sodas: Demineralization Damages Teeth
Fish and Fish Oil for Better Brain Health
Salt: New Research Says Too Little May Be Unhealthy
Bulletproof Coffee: Coffee, Oil, and Butter for Breakfast?

Sugared Soft Drinks: Health Risk? (and What About Diet Soda?)

Sodas in 2-liter bottles

Sodas in 2-liter bottles

When I was a child, one of the greatest treats in our small world was to go to the five-and-dime (a store where many items used to be that price, kids! Example, Woolworths) which had a soda fountain, a long bar serving concoctions like sodas and milkshakes. One of my favorites was a cherry coke — soda water mixed with Coca-Cola and cherry syrup. Serving size for this very sweet drink was probably about 8 oz., or 250 ml. The combination of sweet and carbonation was out of that world! (In other words, a taste combination that stimulated evolved preferences for sweet but far beyond what was usually available in the diet we evolved with.)

Now, of course, sweetened sodas are available everywhere, and sold in much larger serving sizes. My brother was addicted to 7-11 Big Gulps — a massive 30 oz. soda for drinking on the go. Cane sugar was replaced by cheaper HFCS (High Fructose Corn Syrup) as corn was subsidized and sugar controlled at an artificially high price by agribusiness lobbying of Congress. Hamburger fast-food chains built an empire on burgers, fries (potatoes, also a high-glycemic-index food), and soft drinks.

There is evidence that high-carbohydrate diets in general, and sugar in particular, are the cause of the great increase in obesity. Even natural fruit juice and concoctions served in coffee bars have more sugar in one quickly-absorbed dose than is wise.

Politicians have attempted to reduce overconsumption of sweetened soft drinks by limiting serving sizes or proposing special taxes. Most people find these efforts intrusive and they haven’t gotten very far in the political system; like many pleasures, soft drinks don’t cause problems consumed in moderate serving sizes and only on occasion. Trying to force people to change their habits by law or regulation is unlikely to be very effective; widespread public understanding of the problem does seem to be working, however, as soft drink consumption is down and obesity seems to be leveling off in the US though still increasing elsewhere.

Scientists are still studying the effects of sugar on the body, and a recent study reviewed in Science Daily shows another downside of sugary drinks and the large blood sugar spikes they cause:

Research to be presented at the Annual Meeting of the Society for the Study of Ingestive Behavior (SSIB) finds that daily consumption of beverages sweetened with high-fructose corn syrup or sucrose can impair the ability to learn and remember information, particularly when consumption occurs during adolescence.

Both adult and adolescent rats were given daily access to sugar-sweetened beverages that mirror sugar concentrations found in common soft drinks. Adult rats that consumed the sugar-sweetened beverages for one month performed normally in tests of cognitive function; however, when consumption occurred during adolescence the rats were impaired in tests of learning and memory capability.

The lead author, Dr. Scott Kanoski from the University of Southern California, says, “It’s no secret that refined carbohydrates, particularly when consumed in soft drinks and other beverages, can lead to metabolic disturbances. However, our findings reveal that consuming sugar-sweetened drinks is also interfering with our brain’s ability to function normally and remember critical information about our environment, at least when consumed in excess before adulthood.”

In addition to causing memory impairment, adolescent sugar-sweetened beverage consumption also produced inflammation in the hippocampus, an area of the brain that controls many learning and memory functions.

Which confirms another hazard of frequent consumption of highly-sweetened soft drinks: a period of poor learning ability after each serving. Which is likely to give ammunition to schools that ban them in lunchrooms or vending machines.

But what about diet drinks sweetened with the usual artificial sweeteners like aspartame or sucralose? One concern has been that these drinks set off the body’s insulin release because they trigger sweet receptors just as sugar does, but the insulin causes more harm since it has nothing to work on — the body has been tricked. This theory has been used to support the idea that diet soft drinks will increase cravings for sweets and cause other problems that make avoiding them wise. But the evidence of this is very thin, one recent study showed no ill-effects, and I personally enjoy occasional diet soft drinks without problems. Most likely diet soft drinks in moderation cause few problems for those who aren’t sensitive to the specific sweeteners used.

Note that many sodas — and fruit juices like orange juice — are highly acidic and can erode tooth enamel over time. In other words, if you drink Diet Coke all day long, your tooth surfaces will quickly be decalcified and start to deteriorate. This is another good reason to avoid frequent consumption of these drinks.

For more on diet and weight loss:

Getting to Less Than 10% Body Fat Like the Models – Ask Me How!
Starbucks, Jamba Juice Make You Fat
Fat Doesn’t Make You Fat. Government Guidelines Did!
‘Fed Up’ Asks, Are All Calories Equal?
Fructose: The True Villain?
More on “Fed Up”, Sugar Subsidies, and Obesity
Another Study on Diet Drinks
LeBron James Cut Carbs for Lean Look
Why We’re Fat: In-Depth Studies Under Way
Almonds: Superfood, Eat Them Daily for Heart Health
Fish Oil Supplements Ward Off Dementia
More on Diet Drinks: Best Studies Show They Aid Weight Loss
Vani Hari: “Food Babe” and Quack
Cleanses and Detox Diets: Quackery
Gluten-Free Diets: The Nocebo Effect
Acidic Soft Drinks and Sodas: Demineralization Damages Teeth
Fish and Fish Oil for Better Brain Health
Salt: New Research Says Too Little May Be Unhealthy
Bulletproof Coffee: Coffee, Oil, and Butter for Breakfast?

Starbucks, Jamba Juice Make You Fat

starbucksfrappuccino

[2006] This article discusses those sweet, caffeinated smoothies Starbucks sells, and their desire to sell them to kids without appearing to market to children directly. They are introducing Frappucino™ juice blends; I don’t see nutritional info on the new drinks on their web site, but they are probably even worse than the existing Frappucinos, which typically have more than 400 calories of (mostly) sugar (80 g carbs) for a 16-oz serving. This is a sugar bomb — drinking one of these will spike your blood sugar, leading to more fat deposition followed by a carb-craving coma.

Note that Jamba Juice-ish smoothies are almost as bad, usually having 200+ calories of sugar in the same 16 oz. format. But juicing fruit lets the liquid sugars enter your bloodstream quickly, whereas fruit itself slowly releases its nutritional value as the cell walls break down in your digestive system, which is much better.

I’m not suggesting (as surely some will) that some government should step in to protect children (or anyone else) from unhealthy processed foods. But the constant advertising of fruit juice as something healthy misleads people into thinking they are choosing wisely when they pick up one of these.

It’s not unusual for people to have several of these concoctions a week. Then they wonder why they can’t stop gaining weight….

For more on diet and weight loss:

Getting to Less Than 10% Body Fat Like the Models – Ask Me How!
Fat Doesn’t Make You Fat. Government Guidelines Did!
‘Fed Up’ Asks, Are All Calories Equal?
Fructose: The True Villain?
More on “Fed Up”, Sugar Subsidies, and Obesity
Another Study on Diet Drinks
LeBron James Cut Carbs for Lean Look
Why We’re Fat: In-Depth Studies Under Way
Almonds: Superfood, Eat Them Daily for Heart Health
Fish Oil Supplements Ward Off Dementia
More on Diet Drinks: Best Studies Show They Aid Weight Loss
Vani Hari: “Food Babe” and Quack
Cleanses and Detox Diets: Quackery
Sugared Soft Drinks: Health Risk? (and What About Diet Soda?)
Gluten-Free Diets: The Nocebo Effect
Acidic Soft Drinks and Sodas: Demineralization Damages Teeth
Fish and Fish Oil for Better Brain Health
Salt: New Research Says Too Little May Be Unhealthy
Bulletproof Coffee: Coffee, Oil, and Butter for Breakfast?