Dispelling nutrition myths, ranting, and occasionally, raving


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Which fitness tracker gives you the best calories burned for your workout? An experiment

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Remember my rant a little while ago about how you shouldn’t think of exercise and food as an equation to balance? Or my post about not using the exercise component of calorie counting apps? Well, I just wanted to add a little more to that conversation today.

I use a Garmin watch to track my runs and occasionally I’ll look at the “calories burned” out of curiosity. After a pretty fast longish interval run I noticed that the calories burned seemed rather low so I started scrolling back through and was puzzled to find a shorter easier run that supposedly resulted in a very similar caloric expenditure. That left me wondering how Garmin determined the calories burned during a run. I looked it up and it turns out that it’s related to heart rate. Sometime the heart rate monitor is wonky and (especially when it’s really cold out) will register a heart rate that would be more likely seen when I’m sitting on my butt than when I’m out booking it through speed work. That means that my Garmin (erroneously) registers minimal exertion and thinks that I’m not burning very many calories.

Today I decided to do a little experiment. I wore my Garmin, as per usual, which is synched to my Strava account. I also fired up the Nike+ Run Club app for the first time in ages and I set out on an easy(ish) 10k run. After the run, I also entered the time spent running at the closest average pace into myfitnesspal. All of these apps have my height and weight. Any guesses what the results looked like?

Garmin: 463 calories

myfitnesspal: 517 calories

Nike: 526 calories

Strava: 1371 calories!!!!

Now, I have no idea how many calories I actually used during this run, I’d wager Garmin was probably closest to the mark considering that the heart rate monitor seemed to be working properly. But Strava, what the actual hell?? Considering that Strava gets all of it’s data from my run directly from Garmin I find it amazing that it estimated I burned nearly three times as many calories as Garmin thought I did. I’m sure that if I had other apps and trackers I would have gotten slightly different results from all of them.

All this to say, if you’re exercising and tracking calories burned, you probably shouldn’t give that number too much weight. Try to think of exercise as giving you health and fitness rather than taking away calories and weight.

 

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Why I hate the caloric math game

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I have a beef with a lot of the all-in-one fitness/weight management apps. Many people benefit from tracking their calories when they’re trying to lose weight. I’m all for that. What I hate is the inclusion of calories burnt through exercise. I think that a lot of these apps over-estimate the number of calories expended during various activities. This can mean that if you’re looking at the bottom-line to determine how many calories you can eat without gaining weight you’re probably going to eat more than you need. I often tell people to either not track their exercise using these apps or to ignore the additional calories the app then tells them that they can have. Just use the nutrition side of the app. It’s wise to remember that even that’s not going to be 100% accurate, especially if you’re not weighing everything you eat. It’s just another weight management tool in a box of many.

Now for the real beef: I don’t like that these apps try to turn weight loss into a math problem. It’s not. We used to believe that cutting 3500 kcal would result in a pound of weight lost. We now know that it’s much more complicated than that. There are many factors contributing to the weight we are. Yes, how many calories we consume (and expend) are a huge factor in determining how much we weigh, and whether we lose, gain, or maintain our weight. I don’t want to diminish that fact. I’m not going to tell you that if you just ate cleaner you would lose weight. The cleanliness of your calories doesn’t matter when it comes to weight loss. However, adding 350 calories by going for a walk is an oversimplification. It may also lead to an unhealthy way of thinking about food, exercise, and weight management.

Most of us easily consume more calories than we’ve burnt after a workout. Exercise makes you hungry and it’s a whole lot easier to eat 500 calories than it is to expend them during a workout. When we start thinking about exercise as a way to “earn” more calories we’re moving away from healthy eating and healthy fitness. While I’ve said that the cleanliness of your calories doesn’t matter for weight loss, and I’ve also said that there should be no forbidden foods, eating primarily nutrient-rich whole foods is important for your health. A session at the gym shouldn’t be a licence to eat high-calorie, low-nutrient foods for the rest of the day. Focus on gaining health through the food you eat and the physical activity you do, rather than the numbers in an app or on a scale.


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Will teenaged milk consumption increase hip fracture risk in old-age?

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I recently saw someone touting the results of a study as indicating that milk consumption may increase the risk of bone fractures. Now, if you’ve been reading my blog for a while you’ll know that I’m not always on board with the promotion of milk. I question the inclusion of milk and alternatives as a food group on Canada’s Food Guide. However, I don’t believe that there’s anything inherently wrong with consuming milk (in moderation) if it’s a beverage that you enjoy. It’s certainly better than juice! Anyway… Despite my posts deriding “research” promoting the consumption of milk (usually of the chocolate variety) I lean towards siding with the milk-drinkers on this one.

The study looked at data from the Nurses’ Health Study and the Health Professionals Follow-Up Study in the US. Milk consumption of participants during adolescence was reported based on dietary recall ten years into the study. Considering that, depending on the study, participants were between 30-55 and 40-75 years of age at the start of the study, they would have been estimating their adolescent milk consumption anywhere from about 17 to 60+ years after the fact. Maybe it’s just me, but at 35 years of age I can’t recall how much milk I drank as a teenager. As dietary recall tends to be inaccurate the day following consumption I would hazard to guess that it’s even less accurate decades down the road.

“Participants were excluded at entry if they had reported a prior hip fracture, a diagnosis of osteoporosis or cancer”. I wonder if this exclusion affected the results. It would be interesting to look at the excluded participants to determine if they were milk-drinkers or not during adolescence. The researchers also divided the results into three groupings: those who consumed milk less than twice a week, those who consumed it once a day, and those who consumed it four or more times a day. Four or more times a day seems like rather a lot of milk to me. I would be interested to see the level of risk for hip fracture played out for those consuming the recommended number of servings based on the Food Guide (i.e. 3-4/day) also taking into consideration other foods from the milk and alternative group.

The researchers found an increased risk of 6% of hip fracture for each glass of milk consumed by men during teenaged-years (this was presumably over the average of 2.1/day reported). Interestingly, for women, there was no relationship between milk consumption and hip fracture risk. The researchers did rely on participants to report hip fractures so there may have been some degree of inaccuracy in the findings.

I think that this statement by the authors in the discussion is worthy of note: “it is not entirely clear that an early gain in bone mass will persist into adult years as the young skeleton is replaced through many years of remodeling, which may erase any initial advantage.” In other words, consumption of nutrients, and participation in exercise, which increases bone density when you’re young may not matter if you don’t carry on with these behaviours as you age. The argument here is less whether or not milk consumption during adolescence affects bone density and hip fracture risk during old age and more that it’s important to continue to be active and to consume foods that are rich in calcium and vitamin D as our bones are not static.


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What’s the benefit of exercise?

I was listening to the radio the other day and they were interviewing a Dr who conducted some research on a physical activity intervention on elementary school children. The segment was introduced as being about obesity. I can’t recall exactly what the intervention was but, naturally, it had no effect on obesity levels in the children.

I know that obesity is the big thing right now (pun totally intended) but I think that we need to stop approaching every study about exercise and nutrition as a weight loss intervention. We already know that diet generally accounts for about 80% of the weight loss equation. Therefore, logically, physical activity interventions are unlikely to have a significant effect on weight.

This focus on obesity causes us to lose focus on other benefits to be had from physical activity. Just because children didn’t lose weight from the intervention doesn’t mean that such interventions aren’t worthwhile. Benefits of physical activity and exercise include: increased healthspan, decreased risk of many chronic diseases (e.g. depression, type 2 diabetes, heart disease, some forms of cancer, osteoporosis, dementia), stronger immune system, increased energy, better quality of sleep, etc. I always say that exercise is my drug of choice.


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The new normal

A recent article in the Globe and Mail discusses How Fat Has Become the New Normal. While, it seems fairly evident that, as a greater proportion of the population becomes overweight or obese, this would tend to normalize that state, this “duh” conclusion is not the focus of my post today. My issue is with the approach taken to combat the obesity “epidemic”. The approach many doctors are reported to be taking, according to the aforementioned article, is “to shift the discussion from weight to activity. Instead of telling people about the importance of losing weight, it could be much more effective to make it easier for people to get out and be physically active in their communities.” I definitely think that shifting the focus from the negative and focusing instead on the positive is essential to reducing obesity rates. However, I don’t think that placing the emphasis on getting people to be more physically active is the solution. Yes, we should be encouraging people to be more physically active, to engage in active transportation, and to get daily exercise. My quibble with this article, and approach, is that there’s no mention of diet. For prevention of weight gain and for overall health, both physical activity and a healthy diet are essential. For weight loss, a healthy diet is far more important than physical activity. Why is this fact so frequently overlooked in discussions of obesity? The solution is not as simple as “getting out” and “moving more” we need to take a long hard look at what we’re ingesting and why.