My nutrition and fitness update: Week 1

Posted by Dave on April 8, 2010 | 5 Comments

When I started this month of posts on fitness and nutrition, I promised that I’d be using myself as a bit of a guinea pig, recording all my food and beverage intake, as well as my exercise. You can see my record here, but the MyFitnessPal site doesn’t do a very good job of summing things up — their reports and graphs are either too detailed or not detailed enough, so I’m going to sum things up for you every week here as well.

As a 6 foot, 2-inch tall man, my weight of 225 pounds at the start of this month puts me squarely in the “overweight” category by most accounts. That corresponds to a body mass index (BMI) of 28.9. The US CDC considers BMIs between 25 and 29.9 to be overweight, but when I entered my information into their BMI Calculator, the results page said I should try to maintain my existing weight. They only recommend losing weight if I have additional risk factors such as high LDL cholesterol or high blood pressure.

But because BMI can be high even in very fit athletes, some organizations are beginning to favor the waist-to-height ratio (W/Ht). My waist (measured at the navel) is about 40 inches, so my W/Ht is 0.54. W/Hts below 0.5 are considered normal, so again, my W/Ht is above normal. According to a 2003 study published in the International Journal of Obesity, this puts me at a significantly higher risk of hyperglycemia, hypertension, hypercholesterolemia, low HDL cholesteral, and fatty liver, among other conditions. Of course, this group is also significantly less likely than the lower W/Ht group to get regular exercise, so it’s unclear whether the high W/Ht is actually directly responsible for the health problems.

But there does seem to be converging evidence that I’m not at my ideal weight, and that’s supported by the ease with which my midsection jiggles. So let’s take a look at what I ate last week and see if my diet is to blame. I tried not to adjust what I ate during this past week compared to a normal week, just make an accurate accounting for everything I consumed. The graph below charts total calories and sodium consumed over the past week (sodium is on this graph because it’s a similar scale to calories):

The green dotted line is the amount of calories the MyFitnessPal web site recommends I consume each day to maintain my current weight. If I want to lose 1 pound per week, as MyFitnessPal recommends, then I need to cut back to the level marked by the blue dotted line, about 1940 calories a day. The green dotted line also happens to fall at about my daily recommended intake of sodium.

So as you can see, I consumed more calories and more sodium than recommended last week. But that doesn’t account for exercise. The blue line gives my exercise-adjusted calories (subtracting the number of calories expended in exercise from my total consumption). Now the line is safely below the maintenance level. In fact, my average daily exercise-adjusted consumption for the week was almost exactly 2,000 calories, which is just a touch more than what MyFitnessPal claims will result in a one-pound-per-week weight loss. As it turned out, my weight decreased by 3 pounds over the course of the week: This morning I weighed in at 222 pounds.

So why did I lose weight when I tried not to change my eating habits? One possibility is the Hawthorne Effect. Even though I wasn’t consciously trying to cut back, perhaps I ate a little less than usual just because I was recording it and reporting back to you. It also could simply be statistical error. My bathroom scale is probably only accurate to ±1 pound, and just having an extra glass of water can increase my weight by a pound, so maybe the apparent weight loss was just coincidence. We’ll see if anything changes over the rest of the month.

But how healthy were the foods I was eating? This graph tracks a number of nutrition factors:

MyFitnessPal suggests that about 55 percent of my calories should come from carbohydrates, 30 percent from fat, and 15 percent from protein. As you can see, I’m eating considerably more carbs than the other categories, so that doesn’t look too bad. But the units for those items are grams. Carbohydrates and proteins average about 4 calories per gram, while fats average about 9 calories per gram. This graph shows carbs, fats, and proteins as a portion of total calories consumed:

The amounts don’t add up to 100 percent, which suggests to me that the MyFitnessPal database isn’t quite right. The dotted lines show the recommended portion of calories consumed, which I then adjusted to account for the database problems. As you can see, I’m doing basically all right with proteins, but my carbohydrate consumption is low and my fat consumption is high, especially on weekends (4/3 and 4/4) when I tend to have bigger, fattier meals.

Looking back to the first two charts, weekends are also a problem for sodium consumption and cholesterol, which goes off the chart on Saturday (1024 mg) and Sunday (732 mg). This was Easter weekend, so I did have a lot of eggs, but an Asian meal Saturday involving soy sauce and skin-on chicken breasts also accounted for huge amounts of both sodium and cholesterol.

Now let’s take a look at exercise. This graph shows the amount of calories I burned by exercise according to the MyFitnessPal calculator:

My primary fitness activity is running. I go for a run every weekday morning except Mondays, when I have a big writing deadline and don’t exercise. I also play a tough, competitive soccer game every Sunday, and Greta and I take ballroom dance lessons and practice dancing once or twice a week, so other than being a busier-than-normal week for dancing, this week was quite typical. At the outset, I told the MyFitnessPal website that I exercised about 30 minutes per day, and the blue dotted line indicates what their calculator predicted that would entail in calories burned. As you can see, when my specific exercises and weight were factored in, I did a lot better than that. I verified the MyFitnessPal calorie expenditure estimates against a couple other calculators, and they appear to be quite accurate. I don’t know how MyFitnessPal arrived at its initial assumption of my calorie consumption, but that estimate, it turns out, was quite low.

None of this takes into account my new plan of standing for a good portion of the day. We’ll see next week if that has a noticeable impact on my fitness.

Hsieh, S., Yoshinaga, H., & Muto, T. (2003). Waist-to-height ratio, a simple and practical index for assessing central fat distribution and metabolic risk in Japanese men and women International Journal of Obesity, 27 (5), 610-616 DOI: 10.1038/sj.ijo.0802259

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