After yesterday’s post on the potential benefits of eating blueberries, some readers noted that one should not discount the calories in fruit. In addition, there appears to be a “myth” out there that because of the sugar in fruit, they should be considered a high-glycemic food and could therefore be counterproductive in weight-loss diets - especially for people trying a “low-carb” approach to weight loss.

On the other hand, dietary guidelines regularly recommend more fruit and vegetables as part of a healthy balanced diet.

So does eating fruit sabotage efforts to lose weight?

This question was addressed by Kerstin Schroder from the University of Utah in a study just published in Nutrition.

Schroder examined the effect of fruit consumption on body weight and weight loss in 77 overweight and obese dieters enrolled in a 6-month randomized controlled trial testing the effects of a computer-assisted dieting intervention program with the goal to decrease energy intake, increase fruit and vegetable consumption, and maintain a balanced diet.

Overall weight loss during the intervention was rather modest (average weight loss of 3.23 lb).

Although vegetable consumption increased as a result of the intervention, fruit consumption did not.

However, after controlling for age, gender, physical activity, and daily macronutrient intake, higher fruit consumption was associated with a lower BMI both at the baseline and the end of the study.

Although overall fruit consumption did not increase, those participants, who did increase fruit consumption, lost more weight. Indeed, difference scores in fruit consumption (which varied from −1.50 to +2.86 servings per day) turned out to be the only significant predictor of weight loss among the nutrition variables, with an incremental contribution of 5.0% to 5.1% of the variance explained in weight loss and BMI change scores.

No such relationship was seen with changes in vegetable intake. Thus, increases in vegetable intake explained only 4% incremental variance in weight loss during the first 3 mo of the trial and explained none of the variance in weight loss over the entire 6-mo period.

The results not only suggest that fruit and vegetables may well have different effects on weight control, but also that eating more fruit by no means reduces the likelihood of weight loss.

Obviously, simply adding fruit to your diet is very unlikely to produce weight loss. Moreover, the study does not tell us if all fruit are equal or if different fruit vary in their ability to promote or sustain weight loss.

Certainly there appears nothing about fruit that warrants either damning them for hampering weight loss nor promoting them as “super foods” for achieving a healthy weight (whatever that may be).

They’re simply a healthy food that should be part of any balanced diet.

AMS
Edmonton, Alberta

Click here for additional posts and comments on my FaceBook pag

Hat tip to Sebely for pointing me to this article

Schroder KE (2010). Effects of fruit consumption on body mass index and weight loss in a sample of overweight and obese dieters enrolled in a weight-loss intervention trial. Nutrition (Burbank, Los Angeles County, Calif.), 26 (7-8), 727-34 PMID: 20022464

Eating more fruit and vegetables is a common recommendation in dietary guidelines to prevent everything from obesity and heart disease to premature aging and cancer.

In this context, berries are of particular interest, as they are particularly rich in anti-oxidants and a variety of phytochemicals like polyphenols, anthocyanins, proanthocyanidins, resveratrol, flavonols, and tannins that have demonstrated beneficial effects in vitro and in vivo studies.

But randomised controlled studies on the health effects of eating berries remain scarce.

It is therefore of interest that Arpita Basu and colleagues from Oklahama State University, in a paper just published in the the Journal of Nutrition, now report the results of a randomised controlled trial of blueberries in men and women with obesity and the metabolic syndrome.

In this study, the researchers examined the effects of eight weeks of daily blueberry supplementation (50 g freeze-dried blueberries, approximately 350 g fresh blueberries) compared to equivalent amounts of fluids in 48 participants with an average BMI of around 38 kg/m2).

While blueberries did not appear to have any effect on serum glucose or lipid profiles, there was a significant decrease in systolic and diastolic blood pressures (-6 and -4%, respectively) versus controls (-1.5 and -1.2%).

There was also a roughly 30% decrease in plasma levels of oxidized LDL in the blueberry group compared to a 9% reduction in controls.

No change in weight was reported.

Although this is a short-term study of only eight weeks duration, the data does suggest that there may be beneficial effects of regular consumption of blueberries on cardiovascular risk factors. Whether or not these effects translate into better health outcomes in the long term remains to be seen.

AMS
Edmonton, Alberta

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Basu A, Du M, Leyva MJ, Sanchez K, Betts NM, Wu M, Aston CE, & Lyons TJ (2010). Blueberries Decrease Cardiovascular Risk Factors in Obese Men and Women with Metabolic Syndrome. The Journal of nutrition PMID: 20660279

One commonly heard propositions to combat the obesity epidemic is to tax soft drinks. No doubt, sugary soft drinks are a common and important source of “empty” calories, but will taxing soft drinks really reduce obesity rates?

This assumption was now examined by Yale University’s Jason Fletcher and colleagues, in a paper just published in Contemporary Economic Policy.

The researchers collected information on taxation of soft drinks with respect to specific excise taxes on soft drinks and other snack taxes, general state sales taxes, and special soft drink exceptions to food exemptions from sales taxes in several US States between 1990 to 2006. Height and weight data was used from the representative NHANES III data set.

Using complicated models accounting for a variety of potential confounders, the authors confirmed that state soft drink taxes have a statistically significant impact on behavior and weight; however, the magnitude of the effect is surprisingly small.

Thus, a 1% increase in the state soft drink tax rate leads to a decrease in BMI of 0.003 points and a decrease in obesity and overweight of 0.01 and 0.02 %, respectively.

There were also significant differences on how soft drink taxes affect different demographic groups. For e.g. a 1% increase in the soft drink tax rate decreases BMI by over 0.01 points for the lowest three categories (income below $20,000) and nearly 0.01 points for the highest category (income above $50,000).

In addition, The impact of state soft drink taxes is larger for females, middle-aged and older individuals, individuals with greater education, and varies according to race and ethnic categories.

The authors point out that soft drink consumption represents only 7% of the total energy intake and one should therefore expect only modest changes in population weight through soft drink consumption responses to small tax increases.

In fact, they estimate that even a 20% increase in soft-drink taxes would only lead to a mean BMI change of 0.06 points, although the impact may be somewhat larger for some demographic groups.

Indeed, even if soft drinks were to be taxed at around 58%, the current average taxation rate for cigarettes,
the researchers estimate that mean BMI in the United States would likely only decrease by 0.16 points and reduce the proportion of overweight or obesity in the population by 0.7%.

In comparison, the between 1990 and 2006, the average increase in population BMI in the US was around 2.3 points.

While the authors conclude that although the effect of increased taxation of soft drink may do little for obesity, they point out that there may be other health benefits, including improvement in dental health.

Additionally, an increase in the soft drink tax of this size would raise considerable revenue for the federal and state governments that could perhaps be used to implement other measure to address the obesity epidemic.

While the authors by no means wish to condone the increased consumption of soft drinks, their analysis clearly suggests that any hope that simply slapping a tax onto soft drinks will somehow reduce obesity rates appears unfounded.

AMS
Edmonton, Alberta

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Fletcher JM, Frisvold D, & Tefft N (2010). Can Soft Drink Taxes Reduce Population Weight? Contemporary economic policy, 28 (1), 23-35 PMID: 20657817

We’ve long known that poor physical fitness and lack of exercise are important risk factors for heart disease.

But matters may be worse, because even for people who exercise regularly, sitting around most of the day may still be an important risk factor for dying of heart problems.

This important impact of sitting around (especially during leisure time) on cardiovascular mortality is reported in a paper by Alpa Patel from the American Cancer Foundation and colleagues just published in the American Journal of Epidemiology.

The researchers analysed data from a large prospective study of US adults enrolled by the American Cancer Society that included 53,440 men and 69,776 women who were disease free at enrollment.

After adjustment for smoking, body mass index, and other factors, time spent sitting (more than 6 vs. less than 3 hours/day) was associated with a 34% mortality risk in women and a 17% higher risk in men of dying during the 14-year observation period.

When both sitting for more than 6 hours/day and low physical activity were combined, mortality risk was around two-fold higher in both men and women compared to those with the least time sitting and the most activity.

The fact that time spent sitting was independently associated with total mortality, regardless of physical activity level, suggests that it is not enough to simply be active, but to also reduce leisure time spent sitting.

The study, obviously does not reveal what it is about sitting that increases risk. One aspect could be that simply standing is in fact a mild form of exercise. Not only, does standing stimulate the cardiovascular system to maintain blood pressure, but standing is also a form of resistance exercise - after all in order to stand, your muscles have to bear and support the entire weight of your body.

Thus, simply standing (rather than sitting or lying down) may provide an important positive stimulus to both the cardiovascular and musculoskeletal system that may well translate into lower risk.

Clearly, if exercise is not your thing, at least look for a job or hobby that keeps you on your feet.

AMS
Edmonton, Alberta

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Patel AV, Bernstein L, Deka A, Feigelson HS, Campbell PT, Gapstur SM, Colditz GA, & Thun MJ (2010). Leisure Time Spent Sitting in Relation to Total Mortality in a Prospective Cohort of US Adults. American journal of epidemiology PMID: 20650954

There is little doubt that changes in diet and physical activity can seriously reduce risk for cardiovascular disease (and countless other conditions from arthritis to cancer).

But changing diet and activity levels both at individual and population levels remains a major challenge. Not that these changes are not possible (they are), but rather that practitioners don’t know where to start and often default to well-meaning but useless advise (eat less - move more).

Last week, the American Heart Association (AHA) Prevention Committee of the Council on Cardiovascular Nursing released a comprehensive collation of the current evidence regarding interventions to promote physical activity and dietary lifestyle changes for cardiovascular risk factor reduction in adults.

Although the document does not specifically address weight management, the principles and learnings from this document certainly apply as much to managing excess weight as they do to dealing with other chronic conditions like hypertension, dyslipidemia or diabetes.

The following intervention strategies and principles meet the highest levels of evidence (Level A or B):

Cognitive-behavioral strategies for promoting behavior change:

• Design interventions to target dietary and PA behaviors with specific, proximal goals/goal setting (Level of evidence: A)

• Provide feedback on progress toward goals. (Level of evidence: A)

• Provide strategies for self-monitoring. (Level of evidence: A)

• Establish a plan for frequency and duration of follow-up contacts (eg, in-person, oral, written, electronic) in accordance with individual needs to assess and reinforce progress toward goal achievement. (Level ofevidence: A)

• Utilize motivational interviewing strategies, particularly when an individual is resistant or ambivalent about dietary and PA behavior change. (Level of evidence: A)

• Provide for direct or peer-based long-term support and follow-up, such as referral to ongoing community-based programs, to offset the common occurrence of declining adherence that typically begins at 4–6 months in most behavior change programs. (Level of evidence: B)

• Incorporate strategies to build self-efficacy into the intervention. (Level of evidence: A)

• Use a combination of the above strategies (eg, goal setting, feedback, self-monitoring, follow-up, motivational interviewing, self-efficacy) in an intervention. (Level of evidence: A)

• Use incentives, modeling, and problem solving strategies. (Level of evidence: B)

Intervention processes and/or delivery strategies:

• Use individual- or group-based strategies. (Level of evidence: A)

• Use individual-oriented sessions to assess where the individual is in relation to behavior change, to jointly identify the goals for risk reduction or improved cardiovascular health, and to develop a personalized plan to achieve it. (Level of evidence: A)

• Use group sessions with cognitive-behavioral strategies to teach skills to modify the diet and develop a PA program, to provide role modeling and positive observational learning, and to maximize the benefits of peer support and group problem solving. (Level of evidence: A)

• For appropriate target populations, use Internet- and computer-based programs to target dietary and PA change; evidence is less for targeting PA alone; adding a form of E-counseling improves outcomes. (Level of evidence: B)

• Use individualized rather than nonindividualized print- or media-only delivery strategies. (Level of evidence: A)

Addressing cultural and social context variables that influence behavioral change:

• Utilize church, community, work, or clinic settings for delivery of interventions. (Level of evidence: B)

• Use a multiple-component delivery strategy that includes a group component rather than individual-only or group-only approaches. (Level of evidence: A)

• Use culturally adapted strategies, including use of peer or lay health advisors to increase trust; tailor health messages and counseling strategies to be sensitive to the cultural beliefs, values, language, literacy, and customs of the target population. (Level of evidence: A)

• Use problem solving to address barriers to PA and dietary change, such as lack of access to affordable healthier foods, lack of resources for PA, transportation barriers, and poor local safety. (Level of evidence: B)
• Nothing revolutionary here or in fact very different from the way most evidence-based weight management programs already work (scams excluded). In fact this list of recommendations provides a valuable checklist to make sure your program is hitting all the relevant buttons

Good to know that there is actually strong scientific evidence to support most of what we do at WeightWise.

AMS
Edmonton, Alberta

Hat tip to Sebely for pointing me to this article

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Artinian NT, Fletcher GF, Mozaffarian D, Kris-Etherton P, Van Horn L, Lichtenstein AH, Kumanyika S, Kraus WE, Fleg JL, Redeker NS, Meininger JC, Banks J, Stuart-Shor EM, Fletcher BJ, Miller TD, Hughes S, Braun LT, Kopin LA, Berra K, Hayman LL, Ewing LJ, Ades PA, Durstine JL, Houston-Miller N, Burke LE, & on behalf of the American Heart Association Prevention Committee of the Council on Cardiovascular Nursing (2010). Interventions to Promote Physical Activity and Dietary Lifestyle Changes for Cardiovascular Risk Factor Reduction in Adults. A Scientific Statement From the American Heart Association. Circulation PMID: 20625115