Tag Archives: cardiovascular disease

Yo-Yo Dieting In Women Has No Effect On Death Rates

Yo-yo dieting isn’t so bad after all.

Fifteen years ago there was lots of hand-wringing in the medical community about the potential dire physical consequences of “weight cycling” – also known as yo-yo dieting. You know, lose a bunch of weight, gain it back, lose it again, gain it back, etc.

After a while, yo-yo dieting as a medical issue dropped off the radar screen. 

A 2009 study in the Archives of Internal Medicine reported on the cardiovascular and mortality effects of yo-yo dieting in women in the massive Nurses’ Health Study. One in four of these women could be classified as weight cyclers. The worst ones were defined as those who lost at least 9.1 kg ( 20 pounds) at least three times.

It turns out the weight cyclers had the same rates of death from cardiovascular disease or any cause as the women who didn’t cycle. They did eventually gain more overall weight as they aged, compared to the non-cyclers.

Note that this study investigated death rates only. So there may have been effects on rates of high blood pressure, diabetes, gout, stroke, etc, that we wouldn’t know about.

Steve Parker, M.D.

Field, Alison, et al. Weight cycling and mortality among middle-aged or older women. Archives of Internal Medicine, 169 (2009): 881-886.

Which Components of the Mediterranean Diet Prolong Life?

Researchers at Harvard and the University of Athens (Greece) report that the following specific components of the Mediterranean diet are associated with lower rates of death:

  • moderate ethanol (alcohol) consumption
  • low meat and meat product intake
  • high vegetable consumption
  • high fruit and nut consumption
  • high ratio of monounsaturated fat to saturated fat
  • high legume intake

Minimal, if any, contribution to mortality was noted with high cereal, low dairy, or high fish and seafood consumption.

The researchers examined diet and mortality data from over 23,000 adult participants in the Greek portion of the European Prospective Investigation into Cancer and nutrition. You’ll be hearing more about the EPIC study for many years. Over an average follow-up of 8.5 years, 1,075 of participants died. 652 of these deaths were of participants in the lower half of Mediterranean diet adherence; 423 were in the upper half.

Alcohol intake in Greece is usually in the form of wine at mealtimes.

The beneficial “high ratio of monounsaturated fat to saturated fat” stems from high consumption of olive oil and low intake of meat.

It’s not clear if these findings apply to other nationalities or ethnic groups. Other research papers have documented the health benefits of the Mediterranean diet in at least eight other countries over three continents.

The researchers don’t reveal in this report the specific causes of death. I expect those data, along with numbers on diabetes, stroke, and dementia, to be published in future articles, if not published already. Prior Mediterranean diet studies indicate lower death rates from cardiovascular disease and cancer.

Steve Parker, M.D.

Reference: Trichopoulou, Antonia, et al. Anatomy of health effects of the Mediterranean diet: Greek EPIC prospective cohort study. British Medical Journal, 338 (2009): b2337. DOI: 10.1136/bmj.b2337.

Additional Information: Childs, Dan. Take it or leave it? The truth about 8 mediterranean diet staples. ABC News online, June 24, 2009. Accessed June 25, 2009.

Addendum:

Here’s a direct quote from the study at hand:

Among the presumed beneficial components of the Mediterranean diet score, high consumption of all but fish and seafood was inversely associated with mortality, although none of these associations was statistically significant.

“. . . none of these associations was statistically significant.” So I can understand some skepticism about this journal article. The researchers had to use some very sophisticated statistical manipulation to come up with the “healthy components” list. I’m not saying that’s wrong. I will admit that the statistical analysis is beyond my comprehension, so I’m trusting the authors and peer-review process to be honest and effective. My college statistics course was too many years ago.

The take-home point for me is that the health benefits of the Mediterranean diet probably stem from an overall combination of multiple foods rather than any single component.

And remember to exercise regularly, maintain a healthy weight (BMI 18.5-25), keep your blood pressure under 140/90, and don’t smoke.

-Steve

Is the Paleo Diet Just a Fad?

Stockholm Palace

The paleo diet—aka Stone Age, caveman, or hunter-gatherer diet—has been growing in popularity since 2009.  Do we have firm evidence that it’s a healthy way of eating?

Swedish investigators at Karolinska Institutet found diminished weight, body mass index, blood pressure, and waist circumference in 14 healthy medical students eating a paleo diet for three weeks.

Published in 2008, this seems to be one of the seminal scientific studies of the paleo diet in modern Europeans.

Their version of the paleo diet:

  • Allowed ad lib: All fresh or frozen fruits, berries and vegetables except legumes, canned tomatoes w/o additives, fresh or frozen unsalted fish and seafood, fresh or frozen unsalted lean meats and minced meat, unsalted nuts (except peanuts – a legume), fresh squeezed lemon or lime juice (as dressing), flaxseed or rapeseed oil (as dressing), coffee and tea (w/o sugar, milk, honey, or cream), all salt-free spices.
  • Allowed but with major restrictions: dried fruit, salted seafood, fat meat, potatoes (two medium-sized per day), honey, cured meats
  • Prohibited: all milk and dairy products, all grain products (including corn and rice), all legumes, canned food except tomatoes, candy, ice cream, soft drinks, juices, syrups, alcohol, sugar, and salt

What Did They Find After Three Weeks?

  • Average weight dropped from 65.2 kg (144 lb) to 62.9 (139 lb)
  • Average body mass index fell from 22.2 to 21.4
  • Average waist circumference decreased from 74.3 cm (29.25″) to 72.6 cm (28.58″)
  • Average systolic blood pressure fell from 110 to 104 mmHg
  • plasminogen activator inhibitor-1 decreased from 5.0 kIE/l to 2.8 kIE/l
  • All of these changes were statistically significant

The researchers looked at a number of other blood tests and didn’t find any significant differences.

Five men and three women completed the study. Of the 20 who originally signed up, one could not fulfill the diet, three became ill (no details), two failed to show up.

So What?

That’s a remarkable weight loss over just three weeks for slender people eating ad lib.

The study authors concluded that these paleo diet-induced changes could reduce risk for cardiovascular disease. They called for a larger study with a control group. (If it’s been done, I haven’t found it yet.)

Sounds reasonable.

It’s too soon to say whether the paleo diet is just a fad.  It will depend somewhat on short- and long-term health effects of paleo-style eating, which may take years to clarify.  On the other hand, it’s hard to imagine large swaths of the population giving up grains, legumes, and dairy products, even if it’s a healthier way of eating.

Steve Parker, M.D.

PS: You’d think they would have said more about the three participants who got sick, rather than leave us wondering if the diet made them ill.

PPS:  I’m considering whether the paleo diet is healthy for people with diabetes.  Follow my progress at PaleoDiabetic.com.

Reference: Österdahl, M; Kocturk, T; Koochek, A; Wändell, PE. Effects of a short-term intervention with a paleolithic diet in healthy volunteers. European Journal of Clinical Nutrition, 62 (2008): 682-685.