Archive for July, 2008

High-Intensity Interval Walking Training Benefits Middle-Aged and Older People

July 23, 2008

In this recent study, walking with high intensity bursts of speed improved health benefits compared to moderate walking (and no walking). Here are the definitions of moderate and high intensity walking:

  • The moderate-intensity group received instruction to walk more than 8000 steps daily at 50% of peak oxygen capacity for a minimum of 4 days per week, and they used a pedometer to monitor steps.
  • The high-intensity group received instruction to do 5 or more daily sets of 2- to 3-minute low-intensity walking intervals (at 40% of maximal oxygen capacity) followed by a 3-minute interval of high-intensity walking (between 70% and 85% of peak oxygen capacity) for at least 4 days per week.

The high intensity group had somewhat better outcomes on these health measurements:

  • At the end of the program, muscle strength for knee extension and flexion increased significantly in the high-intensity group (by 13% for extension and 17% for flexion) vs both the nonwalking and the moderate-intensity groups.
  • There was significant increase in peak oxygen capacity for walking (increased by 9%) and cycling (increased by 8%) in the high-intensity group vs the nonwalking and the moderate-intensity groups.
  • SBP [systolic blood pressure] and DBP [diastolic blood pressure] decreased significantly (by 9 mm Hg and 5 mm Hg, respectively) in the high-intensity group, and the decrease was significantly greater vs the nonwalking and moderate-intensity groups.
  • SBP decreased in 25 of 33 participants with increased peak oxygen capacity for walking in the high-intensity group, which suggests a correlation between the blood pressure and peak oxygen capacity.

While neither conclusive nor dramatic, these results do suggest that increasing walking intensity (for at least 15 minutes, in 3 minute intervals, at least 4 days per week) during regular moderate walking may be helpful for some relatively fit people.

What can we learn from the latest major “diet” study?

July 18, 2008

A major, well-designed research study of the effectiveness of various “diets” on weight loss and health has been published in the current issue of the New England Journal of Medicine. The researchers carefully followed 322 moderately obese people (mostly middle-aged men) for two years in a workplace setting where a lot of support and education was given along with a controlled diet. The research subjects were divided into three groups who ate one of the following: a low-fat, restricted-calorie diet; a Mediterranean, restricted-calorie diet; or a low-carbohydrate, non–restricted-calorie diet.  In the final analysis, all three groups lost weight (mostly in the first six months) and had health benefits, but the Mediterranean and low-carb groups had the best outcomes. Overall, 85% of subjects stuck to their diet for the full 2 years.

What we can learn is that education, structure and support are important in maintaining a consistent eating pattern (this study took place in Israel where the mid-day meal is traditionally the main meal, so the impact of the workplace is significant).  We also learned that the two diets with the best outcomes (in terms of weight loss maintenance, reduction in waist circumference, and some health measures) were the Mediterranean and low-carb. Finally, as written in the original article, we learned:

Mediterranean and low-carbohydrate diets may be effective alternatives to low-fat diets. The more favorable effects on lipids (with the low-carbohydrate diet) and on glycemic control (with the Mediterranean diet) suggest that personal preferences and metabolic considerations might inform individualized tailoring of dietary interventions. … The low-carbohydrate and Mediterranean diets had some beneficial metabolic effects, a result suggesting that these dietary strategies might be considered in clinical practice and that diets might be individualized according to personal preferences and metabolic needs [e.g., diabetics might do better on the Mediterranean diet; people with lipid problems might choose the low-carb diet]. The similar caloric deficit achieved in all diet groups suggests that a low-carbohydrate, non–restricted-calorie diet may be optimal for those who will not follow a restricted-calorie dietary regimen. The increasing improvement in levels of some biomarkers [health indicators] over time up to the 24-month point, despite the achievement of maximum weight loss by 6 months, suggests that a diet with a healthful composition has benefits beyond weight reduction.

One limitation of the study is the fact that most of the subjects were middle-aged men (only 16% were women).

Diet research is hard to do, and this study benefited from having a relatively controlled setting (workplace with main meal being served there). This is also a weakness, because few in the real world have that much structure and support.

The take home message for me is that even with almost ideal conditions it is hard to lose much weight, but weight can be maintained after the initial six months and the health benefits continue in the maintenance phase. Also, the study does help us (a little) choose what kinds of foods to add or subtract from our permanent diet (lifestyle), as opposed to a temporary “weight loss” diet. So, for example, I may decide to add more fish and chicken (and less red meat), more Tabouli (I love it), and less sugar and starch (if I cut way down on these, I won’t have to count Calories so much). Nothing we didn’t already kind of know, but this is reinforcement for that.

For a more detailed summary of the research see this site.

Weight loss strategies

July 16, 2008

This research report appeared in the current news summary from medscape.com. The study only shows associations and not cause and effect, but is worth noting because of the large number of people surveyed.  Though not conclusive, the report reinforces the advice to self-weigh regularly, eat breakfast daily, and avoid fast-food.

July 8, 2008 — Overweight or obese adult patients with type 2 diabetes who followed various weight-loss interventions had lower body mass indexes (BMIs), according to the results of the Action for Health in Diabetes (Look AHEAD) clinical trial reported in the July issue of Diabetes Care [2008;31:1299-1304].

This is a cross-sectional study within an ethnically diverse population with type 2 diabetes from 16 US centers (the Look AHEAD study) to correlate eating patterns with BMI and to describe the most common weight-control strategies in patients with type 2 diabetes.

“Intentional weight loss is recommended for those with type 2 diabetes, but the strategies patients attempt and their effectiveness for weight management are unknown,” write Hollie A. Raynor, PhD, RD, from the Brown Medical School/The Miriam Hospital in Providence, Rhode Island, and colleagues from the Look AHEAD Research Group. “In this investigation we describe intentional weight loss strategies used and those related to BMI in a diverse sample of overweight participants with type 2 diabetes at enrollment in the Look AHEAD. . . clinical trial.”

Study Highlights

  • The Look AHEAD study included 5145 patients aged 45 to 74 years with type 2 diabetes with a BMI of 25 kg/m2 or more (or 27 kg/m2 or more for those receiving insulin), with 33% of participants from ethnic minority groups.
  • Excluded from this analysis were those with inadequate control of diabetes and with underlying diseases that influenced lifespan.
  • Weight-control practices included a list of 23 behaviors that participants chose from, expressed as a percentage of participants using each practice and duration of use of each practice, up to 52 weeks.
  • Those who self-weighed weekly had a lower BMI (35.3 kg/m2) vs those who weighed themselves once a month.
  • Those who consumed 6 or more breakfasts weekly had a lower BMI of 35.6 kg/m2 vs those who consumed 3 to 6 days per week (36.7 kg/m2).
  • Overall, participants consumed 1.9 fast-food meals per week.
  • BMI was 35.1 kg/m2 for those reporting no fast food per week vs 36.9 for those reporting 3 or more fast-food meals per week.
  • The 3 most prevalent weight-control practices by duration of use were increasing fruit and vegetable intake, cutting out sweets and junk foods, and reducing consumption of high-carbohydrate foods, with duration of practice from 20.3 to 26.5 weeks.
  • Overall, a larger amount of intentional weight loss, self-weighing less than once weekly, and more fast-food meals consumed were associated with a higher BMI, whereas consuming more breakfasts was associated with a lower BMI.

What does 200 Calories look like?

July 9, 2008

Click here to see many examples of what 200 Calories looks like. This is a great set of photos, thanks to Joe AverageFor another set of amazing photos, click here (you won’t forget these).

“I’m going to get healthy, starting tomorrow!”

July 7, 2008

I have been putting off blogging, so procrastination seems like an appropriate topic. Procrastination is a major reason we may fail to adopt healthy behaviors we know will help us. A recent discussion on NPR led me to this very useful site which summarizes research on procrastination and offers many suggestions for overcoming it.  For example, Dr. Timothy Pychyl has found that people (especially women) who are able to forgive themselves for procrastinating are then able to move on and accomplish their goal(s).  Self-forgiveness is therefore an important coping mechanism for those of us who delay starting a project (or avoid finishing it).  Also, research suggests that whether we are a healthy “self-oriented” perfectionist or a less healthy “socially-prescribed” one has a lot to do with how much we tend to procrastinate:

Not only do individuals who report higher socially-prescribed perfectionism procrastinate more, but individuals who are described as self-oriented perfectionists actually procrastinate less than non-perfectionists! Clearly, at least in terms of procrastination, there are adaptive and maladaptive forms of perfectionism.

Here is a test to see how much of a perfectionist you are; it takes about 30 minutes to do, is scored online, and gives you some indication about what sub-type you are (but you will have to pay to get more detailed information).