How Fitness Trackers Sabotage Weight Loss

Lots of people use diet and activity trackers to log their food intake and exercise. After all, there’s an old saying that “you can’t manage what you don’t measure.” And yet it seems to be backfiring.

I get email after email from people using these trackers who can’t understand why they’re not losing weight. They’re entering in every morsel of food and logging every activity. According to their trackers, they should be shedding two or three pounds a week. And yet the scale hasn’t budged—or they’ve actually gained weight!

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The problem with net calories

Here’s how many of these trackers work: You start every day with a certain number of calories to spend. That number is based on your height, weight, age, sex, activity level, and your goals—that is, whether you’re trying to lose, gain, or maintain your current weight.

Calories are subtracted from your balance as you log your meals into the diet tracker over the course of the day. Ideally, you don’t get to zero too early in the day. But if you do, there’s a solution. Let’s say it’s 5 pm and I’m down to my last 400 calories. But wait! I can take an evening run, log it into the app and now I’ve got 840 calories to spend on dinner! How awesome is that?

The general principle here is sound: The more you move, the more you can eat. In practice, however, these “net calorie” calculations are inaccurate and misleading—and they are suckering people into eating too many calories. Let me explain.

How logging exercise leads you astray

Although diet tracking apps can help you get an accurate picture of your calorie intake, they are much less reliable in determining how many calories you burn. Here are at three ways they tend to get it wrong.

Mistake #1: Your baseline may be too high.  In order to calculate your baseline calorie requirements, you indicate your activity level: sedentary, lightly active, moderately active, or very active. This does not refer to how much you exercise (we’ll get to that in a moment). This is just about your daily activity level. And guess what? Most people select an activity level that’s one or two categories higher than their lifestyle actually warrants. Unless you rope cattle eight hours a day, your lifestyle probably does not qualify as “very active.”

If you use a wearable fitness tracker like a Fitbit or Apple Watch or even a low-tech pedometer or step counter, you can use that to help you select the proper category for your lifestyle. Here’s an easy cheat sheet:

  • Fewer than 1,000 steps a day is Sedentary.
  • Fewer than 10,000 steps or about four miles a day is Lightly Active.
  • Ten to 23,000 steps or four to 10 miles a day is considered Active.
  • More than 23,000 steps or 10 miles a day is Highly Active.

If you walk or run for exercise, you can count those steps and/or miles toward your baseline activity level if you want, but then you can’t enter them again as exercise. They’ve already been counted.

Mistake #2: The calories burned from additional activity are often overestimated.  Most diet tracking apps give you a place to manually log physical activities and exercise, such as a spinning class or yard work or ballroom dancing. Alternatively, there are wearable devices that sense your movement and changes in your heart rate.  Either way, you may not be burning anywhere near as many calories as your app thinks. As with the readouts on the aerobic equipment at your gym, diet and fitness trackers may overestimate calories burned by anywhere from 10% to 25%.

For one thing, the more you do a given exercise, the more efficient your body becomes at performing that motion. As a result, you burn fewer calories. The first time I run an eight-minute mile, I’m probably going to burn more calories than the 100th time I run an eight-minute mile.

Not only that, but when we burn a bunch of calories exercising, our body actually adjusts by burning fewer calories the rest of the day.  A new study finds that the body of a reasonably fit person may “recover” up to 28% of the calories burned through exercise by burning fewer calories at rest.  Ironically, the more fat tissue you have, the greater this effect.  As researcher John Speakman explains,

“When your smart watch tells you that you burned 300 calories on your run it may be correct (probably isn’t). But even if it is correct, you should not be deluded into thinking you can now eat 300 calories more food.”

Mistake #3: You may be counting some of those calories  twice.  If I spend the next hour sitting at my computer writing this podcast episode, I’ll burn about 100 calories. Those non-active calories are already accounted for in my daily calorie allowance. If I spent the next hour on the stationary bike instead, I’d burn 500 calories. That’s 400 more calories than I would have burned writing this episode. But if I log my bike ride into my diet tracker, it doesn’t add 400 calories to my total allowance … it adds 500. Essentially, it counts those 100 baseline calories twice.

The more activities you enter in to your exercise diary, the more this double-dipping error compounds—especially if you’re logging a lot of low-intensity activities like housecleaning or yoga.

I recently heard from a Nutrition Diva listener who said she burned 3,000 calories a day. She was only eating 2,500. She couldn’t figure out why she was gaining weight.  Sure enough, she was using an app to track her food intake and exercise.

According to her app, her baseline calorie needs were about 1,800 calories a day. She then logged activities for almost every hour of her day: making beds, folding laundry, unloading the dishwasher, yoga class, walking the dog, grocery shopping, car-pool, weeding the garden, playing the piano, cooking dinner, folding laundry, and so on. According to her tracker, all those activities were burning an extra 1,200 calories a day—which gave her a total “net calorie” allowance of 3,000 calories a day. She figured she could eat 2,500 calories a day and still lose weight.

In reality, all of her routine activities probably only burned a couple hundred calories above and beyond her baseline. Instead of eating 500 calories less than she burned each day, she was really eating 500 calories more than she burned each day. No wonder she wasn’t losing weight!

How to avoid the net calorie trap

Activity trackers are a great way to keep track of how active you are, but they aren’t very accurate at estimating your calorie expenditure. Adding “calories burned” to your daily calorie allowance can result in unintended weight gain.  So, I’d suggest that you don’t log your exercise and other activities into your diet tracker or sync your wearable fitness tracker to your diet log. Even better, I’d encourage you to stop thinking of exercise as simply way to burn calories or earn food and focus on the many other benefits it provides instead.

See also: What if exercise burned zero calories?

Sources

  1. Careau, Halsey, et al.. Energy compensation and adiposity in humans. 2021. https://www.cell.com/current-biology/fulltext/S0960-9822(21)01120-9.

 

Originally published at QuickandDirtyTips.com

Metabolism Myths

Despite the recent popularity of intermittent fasting, there’s still a widespread belief that eating several small meals a day promotes weight loss by stoking your metabolism. Or that going too long between meals will cause your metabolism to slow down. I think one of the reasons that these notions have gotten so much traction is that people haul out some very scientific-sounding explanations that seem, well, very scientific and, therefore, believable.

There are two basic arguments and we’ll tackle them one at a time:

This article is also available as a podcast. Click to listen:

Going into power-saving mode

The first goes like this: your body, when deprived of food for a period of time, will go into “starvation mode.”   This is when the body burns fewer calories in order to conserve energy, just in case the food shortage continues. During a famine, you’d need to live on your stored fat. Down-regulating your metabolism is a way to make those fat stores go a bit further.

It’s similar to the way your laptop adjusts its energy usage when it’s running on batteries, by making the screen a little dimmer, for example. When food is plentiful again, your metabolism goes back to normal, just the way your screen gets brighter when you plug your laptop back in.

If there were actually a famine, you’d be glad that your body is designed this way. But, if you’re trying to lose weight, the last thing you want is increased fuel efficiency. You want to be burning through stored fat like an Escalade burns through a tank of gas. So, the trick is to reassure your body that there is no shortage of food by eating every few hours. Your body will oblige you by continuing to burn calories with reckless metabolic abandon. Or so the story goes.

It makes sense, doesn’t it? And, it’s sort of true. Your body does respond to a prolonged fast by slowing your metabolism to conserve energy. Here’s the thing, though: your body doesn’t go into starvation mode if you go four hours without food. In fact, it takes about three days of fasting or serious caloric restriction for your body to respond with any sort of metabolic adjustment.

The cost of doing business

The second argument, which sounds even more technical and is, therefore, even more impressive, has to do with something called the thermic effect of food.  This is a term that scientists use to describe the energy that your body expends releasing energy from your food.

Think of it as a sort of transaction tax that your body charges you to convert the energy in your food into a form of energy your cells can use. If meal contains 300 calories worth of food energy, converting that food energy into cellular energy might use up 30 calories or so. So you’d end up with just 270 calories worth of energy when it’s all over. It’s a little like changing money in a foreign country. In order to convert your dollars into euros, you have to pay the money-changer a fee.

Some people have interpreted this to mean that if your body is constantly in the process of digesting food, it will constantly be burning calories (via the thermic effect of food) and that if you go too long between meals, you will be missing out on this calorie-burning opportunity.

Bosh! Just like at the money-changer, the fee to exchange food energy into body energy is simply a percentage of how much you’re changing. It doesn’t matter whether you exchange all your money in one lump sum at the beginning of your trip or change small amounts of money three times a day. The fees will be based on how much money you convert. And the thermic effect of food is based on how much you eat, not when you eat it.

The bottom line

There’s nothing wrong with eating six small meals a day instead of the traditional three-square. Some people find this works better for them. For example, you may find that you make better dietary choices if you don’t let yourself get as hungry between meals. But rest assured that going 4—or even 12—hours between meals will have virtually no effect on your metabolism.

It’s also not necessary to eat every few hours in order to keep your blood sugar steady. In fact, spacing your meals out more can have some very beneficial effects on your blood sugar and on other aspects of your health, as well.

Evidence-based nutrition: 3 ways to increase TEF and burn more calories

1. Eat your biggest meals early in the day

Eating more often won’t necessarily affect the TEF. But eating earlier in the day might. Although the research is limited, you might use 30% more calories digesting a meal eaten in the morning than you would if you ate the same meal in the evening. In one study, that amounted to 90 extra calories a day. And this may be one of the reasons that people who eat more of their calories earlier in the day lose more weight. However, most of us follow the opposite pattern, eating most of our calories in the second half of the day.

2. Eat more protein and less fat

The balance of macronutrients (protein, fat, and carbs) in a meal also affects TEF. It takes more energy to digest protein than it does to digest carbs or fat. In other words, the metabolic money changer levies a higher transaction tax to exchange protein into energy, much the way you might pay a surcharge to exchange traveler’s checks rather than cash. As a result, you’ll burn more calories digesting a high protein meal than you would digesting a low protein meal that has the same number of calories.

Protein is definitely king when it comes to TEF, but is there any meaningful difference between carbs and fat? Again, the research is quite limited, but some studies suggest that a meal that is higher in carbohydrates and/or fiber will have a higher TEF than one that is high in fat.

3. Eat less processed foods

One interesting study found that more highly-processed foods have a lower TEF than more minimally-processed foods. It’s more costly for your body to release the stored energy in whole grains, vegetables, or legumes than it is to release the same amount of stored energy in chips, doughnuts, and energy drinks.

The bottom line

In terms of the thermic effect of foods, it doesn’t matter how often you eat. If you want to maximize the effect of diet-induced thermogenesis, eat earlier and increase your protein. It may also help to avoid meals that are high in fat and/or highly processed foods.

But rest assured that going 4—or even 12—hours between meals will have virtually no effect on your metabolism. It’s also not necessary to eat every few hours in order to keep your blood sugar steady. In fact, spacing your meals out more can have some very beneficial effects on your blood sugar and on other aspects of your health, as well.

Sources

  1. W P Verboeket-van de Venne. Influence of the feeding frequency on nutrient utilization in man: consequences for energy metabolism. European Journal of Clinical Nutrition. 1991. https://pubmed.ncbi.nlm.nih.gov/1905998/.
  2. Bo, et al.. Is the timing of caloric intake associated with variation in diet-induced thermogenesis and in the metabolic pattern? A randomized cross-over study. International Journal of Obesity. 2015. https://www.ncbi.nlm.nih.gov/pubmed/26219416.
  3. Anne Raben, et al.. Meals with similar energy densities but rich in protein, fat, carbohydrate, or alcohol have different effects on energy expenditure and substrate metabolism but not on appetite and energy intake. American Journal of Clinical Nutrition. 2003. https://www.ncbi.nlm.nih.gov/pubmed/12499328.
  4. Neal D Barnard, et al. The effects of a low-fat, plant-based dietary intervention on body weight, metabolism, and insulin sensitivity. American Journal of Medicine. 2005. https://pubmed.ncbi.nlm.nih.gov/16164885/.
  5. Sadie B. Barr. Postprandial energy expenditure in whole-food and processed-food meals: implications for daily energy expenditure. Food and Nutrition Research. 2010. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2897733/.

This article was originally published at QuickandDirtyTips.com

Can Your Diet Reduce Stress?

Kristin writes:

Can you talk about cortisol and how it affects our bodies? With all this COVID craziness, it feels like my stress levels are high all the time. What nutritional things can we do to help our stress levels? What can we do about the belly fat that being stressed makes us hang onto?

This article is also available as a podcast. Click to listen

Kristin is not the only one feeling more stressed in recent months. The American Psychological Association conducts an annual poll to gauge stress levels. The specific things that people are stressed about change from year to year but the overall level of stress remains fairly constant.

Even in the best of times, a majority of Americans report living with moderate to high levels of stress and also feel that their stress levels aren’t healthy. Not surprisingly, a new poll conducted in April and May of 2020 found that reported stress levels have jumped up considerably in response to the pandemic.

As many of us know all too well, reaching for sweets or other comfort foods is a typical coping mechanism when we’re stressed. With many people cooped up at home, stress and boredom eating is on the rise, leading to weight gain. And as if that weren’t bad enough, research suggests that when we’re stressed, those comfort calories may lead to weight gain more quickly.

Wouldn’t it be great if there were foods or nutrients that could defuse anxiety and ward off the negative effects of daily stress? No wonder that I see so many magazine and web articles about “stress-busting foods!”

Unfortunately, a lot of these are just puff pieces with little to no scientific basis. Sometimes, however, journalists interview actual scientists about their research. The problem is that researchers often use the word “stress” to mean something very different than what the general population thinks of as stress—and that often leads to confusion.

Physiological stress vs. psychological stress

When we say we’re stressed, we usually mean that we feel overwhelmed or anxious—too many demands, deadlines, and worries, and not enough time, money, and energy to get it all done.

Researchers, on the other hand, often measure physiological stress responses, which don’t necessarily correspond to our psychological experience. So, when they report that a food or nutrient has an effect on “stress,” that doesn’t necessarily mean that you’ll feel better or worse when you eat it.

Let me give you an example.

Do refined carbs cause stress?

In a story on the connection between diet and stress, researcher Robert Ludwig told NPR’s Morning Edition about an experiment he did on obese teenage boys in which the boys who ate highly-processed cereal for breakfast had higher levels of adrenalin (a stress hormone) than those who ate a high protein breakfast instead. The boys who ate more protein were also less hungry and ate fewer calories at lunch. Chalk one up for a high protein breakfast!

Unfortunately, no one asked the boys about their mood or perceived stress level, so we don’t know whether the different meals had any effect on whether they felt any more or less stressed. Nonetheless, if you heard the piece, you probably concluded (as did the reporter) that eating lots of refined carbs and sugar will make you feel more stressed and anxious.

Or do refined carbs calm you down?

But hang on! In her book The Serotonin Power Diet, Dr. Judith Wurtman claims that a big dose of refined carbohydrates is exactly what you should eat to feel more relaxed and happy. That’s because refined carbohydrates promote the production of serotonin, a “feel-good” neurotransmitter.

So which is it? Are we supposed to eat carbs or avoid them to beat stress?

The reason these two scientists seem to be contradicting one another is that they are measuring completely different things. Ludwig is looking at the effect of diet on adrenal hormones, and Wurtman is describing the effect of diet on neurotransmitters. Of the two, neurotransmitters probably have a closer relationship to our mood.

The reason these two scientists seem to be contradicting one another is that they are measuring completely different things.

Nonetheless, I think the disadvantages of Wurtman’s approach outweigh the benefits. Eating refined carbohydrates may temporarily boost serotonin levels. (After all, that’s probably why we crave them when we feel stressed!) But they also sent your blood sugar, insulin, energy, and appetite on a roller coaster ride. Riding that roller coaster on a regular basis is a good way to increase your risk of Type 2 diabetes and heart disease.

Fortunately, eating refined carbs is not the only way to boost those mood-enhancing neurotransmitters. A few minutes of aerobic exercise, exposure to sunshine, doing a nice favor for someone, or even simply smiling, are all proven ways to reduce your mental and emotional stress levels – without the negative effects of a carbohydrate binge.

Can probiotics reduce stress levels

There is one stress-reducing dietary strategy that might be worth a try. The bacteria that thrive in our guts appear to affect both our adrenal stress hormones and our neurotransmitters. Translation: Prebiotic and probiotic foods may help reduce anxiety and depression and improve our state of mind.

The more different kinds of beneficial bacteria in your gut, the better. So rather than put all of your probiotic eggs in the yogurt basket (as it were), try to branch out with other types of fermented and cultured foods—such as fermented soy products like tempeh, natto, and miso—and lacto-fermented vegetables (which is the fancy new name for old-fashioned pickles). But wait, it gets even better: Cheese, beer, and red wine are also sources of probiotic bacteria. (Enjoy them responsibly!)

The more different kinds of beneficial bacteria in your gut, the better.

On the prebiotic side of things, you can further encourage diversity by providing your gut bacteria with lots of different types of fiber. So, instead of relying on a single fiber supplement to meet your fiber quota, try to get your fiber from a variety of different grains, legumes, nuts, fruits, and vegetables. As is so often the case, eating a variety of whole foods offers more benefits than a diet made up of a short list of superfoods

How to beat stress belly

Finally, is there anything we can do to fend off stress-related belly fat? It’s true that chronically high cortisol levels may trigger the body to store fat preferentially around the middle. Talk about adding insult to injury!

Expecting food, which is a source of energy, to burn fat, which is a form of stored energy, is a little like expecting an ice cube to warm up your coffee.

But despite what you’ll see online, there aren’t any foods that specifically burn belly fat. Expecting food, which is a source of energy, to burn fat, which is a form of stored energy, is a little like expecting an ice cube to warm up your coffee.

The best way to prevent stress-related belly fat is to reduce your stress levels. I know that’s easier said than done these days. A certain amount of stress during a global pandemic and economic crisis is inevitable. But some of it is optional.

Here are a few ways that I’ve been keeping my stress levels as low as possible:

  • Limit consumption of news to the absolute minimum needed to stay informed
  • Choose books, movies, music and friends that you find uplifting and avoid those that you find draining or depressing
  • Get offline and get outside every day
  • Move your body—ideally, in ways you enjoy !
  • Get enough sleep

Your body perceives a lack of sleep as stress. Those who skimp on sleep tend to have higher cortisol levels, which may help explain why under-sleeping is consistently linked with weight gain.

If you’re too stressed to sleep, a guided meditation or yoga Nidra practice can be a great way to calm your mind and body and help you relax into restorative sleep. Check out one of the many meditation or mindfulness apps, such as Headspace, Calm, or my favorite, Insight Timer.

Even when the current crisis has abated, life will continue to be stressful. So learning how to keep stress from damaging your health (or your diet) will not be wasted effort!

Originally published at QuickandDirtyTips.com

Should you throw out your nonstick pans?

 

I’ve been getting lots of questions relating to the documentary Dark Waters.

For example, Dannette wrote:

“I just  watched the movie “Dark Waters” which makes the case against Teflon.  I immediately threw away my nonstick pans. I’m concerned about ALL nonstick surfaces now. I’m not sure if I need to be. I’d love it if you watched it and then let me know what you think. I love having a good nonstick pan, but it isn’t worth my family’s long term health. I just want to figure out what my best options are for being completely safe cooking for my family.”

7/5/20 UPDATE: In my original response (posted here on June 25th), I disclosed that I had not seen the movie Dark Waters.  Unfortunately, that did not keep me from making some false assumptions about it.   In response to valid criticisms, I’ve removed my original comments about the movie Dark Waters, which included some inaccuracies.  (See the comments for several thoughtful descriptions of the movie).

This doesn’t change my answer to Dannette’s question. Although I don’t personally use it, I don’t think users of modern nonstick cookware need to be concerned about chemicals leaching into their food.  But let me add some additional context:

Although PFOA persists in the environment,  it is no longer used in nonstick cookware.  And even when it was used in Teflon cookware, the primary threat was not due to exposure from use of the pans but from industrial dumping of the chemical into the water supply.

Although I’m not afraid of poisoning myself or my family by using nonstick cookware,I prefer to use stainless steel, cast iron, glass, and silicone. I use a little oil or cooking spray when necessary.  I sometimes have to clean a pan.

But the choices that we make individually about which products we use do not necessarily protect us from industrial chemicals that may be harmful to the environment in which we all live.

There are ongoing, legitimate concerns about the process by which industrial chemicals are tested and approved for safety and impact on the environment, including downstream effects on wildlife and human life.

Thank you to all who helped clarify this issue.

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