Monday, October 24, 2011

Nutrition 101 - Part 2 Calories & Nutrients

Nutrition 101 - Part 2


As alluded to in part 1, we derive the energy for bodily functions and movement from what we eat and drink. This energy is measured in calories – the energy currency of our bodies. We also now understand that if we know how many calories we’re expending, we can eat less or more than this amount in order to lose or gain weight respectively.
Many people confuse calories and nutrients. They are not interchangeable terms as they’re entirely different things. Calories measure the energy that nutrients provide our bodies. So when people claim, “not all calories are created equal,” what they’re really implying is the varying nutrients have different effects in the body. But a calorie is always a calorie just as an inch is always an inch… it’s a unit of measurement.

While both calories and nutrients are extremely important relative to your goals, we’re going to talk about calories here.

As it turns out, humans fail miserably at estimating calorie intake. There’s a bunch of research that confirms this. As James Krieger, a researcher and authority on nutrition who’s worth listening to, points out in this article, even dietitians aren’t very good at monitoring calorie intake. You can write down everything you eat and chances are you’ll still mess it up.

This is highlighted in a 60-minute documentary titled  10 Things You Need To Know About Losing Weight. In the documentary, an obese woman believes she has a slow metabolism. They follow her into the testing facility where it’s confirmed that her metabolic rate is perfectly normal. In an attempt to figure out why she’s obese if her metabolism is working properly, she records all of the food she eats over a 9 day period. The first four days she recalls what she ate at the end of each day on video. The final 5 days she records her food consumption in a food diary after each and every meal.

Of course the idea is to uncover the fact that she’s eating more calories than her body needs, thus explaining the excess body weight. What’s really cool is they also had her drink doubly labeled water, which I discussed in the above section. This stuff let the researchers accurately compare how many calories the woman actually ate to the amount that she believed she ate.

After the 9 days the video record, the written record, and the urine samples (for the doubly labeled water testing) were sent to the lab in order to figure out what’s going on, calorically speaking.

Drum roll please…

In her diaries, she estimated eating well below 2,000 calories per day. The doubly labeled water, on the other hand, showed that the woman was underestimating her calorie intake by well over 1,000 calories per day. The dietitian in the documentary states to the woman, “You’re actually forgetting 60% of what you’re eating.”
Some people lie to themselves. Others are simply forgetful. Others have such automatic nibbling habits that they don’t even realize when or how much they’ve eaten. I highly recommend the book, Mindless Eating, to see just how tricky calorie consumption can be given the way that our minds work.

Irrespective of what’s fueling the inaccuracies, most people aren’t going to be able to reasonably assess their own calorie intakes.

To improve accuracy, we ask many of our clients to use a digital food scale. If you weigh every morsel of energy that passes your lips, you’re likely to get a much more accurate estimation. Some people stop short of this by using measuring cups and spoons. This can lead to some problems, which my friend Leigh Peele brilliantly highlighted in  this video. Buy a scale.

You can then record your intake on a free website, an excel spreadsheet, or on good old paper. Some websites that I like for recording purposes include:

The nice thing about these sites is they’re database driven. This means all you have to do is input the type and amount of food eaten and it computes the number of calories and nutrients for you. If you’re recording in excel or on paper, you can rely on the United States Department of Agriculture’s database to find the nutrition information of your weighed foods.

Are you doomed to weighing and recording everything that you eat from here on out? Absolutely not. I view it as a temporary step used to familiarize yourself with portion sizes and the calorie-density of various foods. It’ll increase your awareness and insight of calorie consumption.

Some people stop after 2-4 weeks of consistent logging. Others continue forever. It’s a judgement call you’ll have to make.

Once you’ve calculated your daily energy expenditure, the question then becomes, “How much under my DEE do I want to set my calories to trigger fat loss?” (or over if the goal is weight gain). Remember that if you were to set your calorie intake at the same level of your DEE, in theory your weight would be stable, which is why this intake is referred to as maintenance.

It’s traditionally suggested that you subtract 500 calories from your maintenance level per day. This 500 cal/day would net a 3,500 calorie deficit by the end of 1 week. Since there are 3,500 calories in 1 pound of fat, it’s a simple way to lose 1 pound of fat per week. Or so it seems.

Many people quickly learn that this simple formula doesn’t typically pan out in the real world. There are a number of reasons why it doesn’t – most notably is the fact that as we lose weight, our metabolic rate drops. Most of this is due to the loss of tissue… which means less mass to support and move around. Some of this has to do with what’s referred to as adaptive thermogenesis (or zomg! the starvation mode), which is basically your body shifting into conservation mode in response to the energy shortfall.

The formula also fails quite often due to the fact that even if metabolic rate was static, very few people come close to accurately creating a 500 cal/day deficit. As noted above, it’s common to have people
underestimating their calorie consumption and overestimating their calorie expenditure. Not to mention the fact that the 3,500 calorie/week deficit assumes we’re losing fat tissue and nothing else, which is rarely the case.
Put simply… the rate of weight loss is not always linear.

 Of course when the formula doesn’t pan out… when people don’t lose their targeted 1 lb of weight per week… they blame it on calories not working rather than the obvious. Manage your expectations according to reality! If you expect to lose weight each and every week and to reach your goal weight looking exactly like the model on the cover of your favorite magazine, you’re likely to wind up disappointed and frustrated.

We have an alternative solution.

What you estimate your energy expenditure to be isn’t all that important compared to what you do after you estimate it. Remember, you’re not signing a binding contract here. You’re simply estimating how many calories your body burns in a day. From there, you can set calorie intake above or below your estimation in order to gain or lose weight respectively.

Our recommendation is to autoregulate this intake on the fly based on what’s happening in real time. You don’t set your car to cruise control and expect to arrive at your destination without touching the breaks or turning the wheel, do you?

The process will look something like this:
1. Estimate total daily energy expenditure by multiplying your body weight by 14-16 calories per pound. If you’re obese, relatively sedentary, feel that you have a slow metabolism, or you’ve lost a significant amount of weight in the past… you might consider using 12-14 cal/lb. If you’re very lean, highly active, or feel that you have a fast metabolism… you might consider using 16-18 cal/lb.
2. Set your calorie intake at a level above or below the above estimation depending on whether you want to gain or lose weight, respectively. For fat loss, we suggest a deficit of 20-35% in most cases. For muscle gain, we suggest a surplus of 10-25%. As it turns out, 500 calories above or below maintenance isn’t a bad starting point sans the illogical expectations noted above.
3. Use as many metrics as you can to track progress. The scale is an obvious tool, but it can play games with you – especially when you’re relatively lean and trying to get leaner. For that reason, you should also rely on the fit and feel of your clothes, pictures taken at regular intervals where you’re wearing the same outfit standing in the same lighting and the same distance from the camera, and measurements with a soft tape measure. If you have access to body fat % testing, you could use this as well, though I don’t use it with my clients. Track your metrics every 2-4 weeks.
4. Based on the trend you’re seeing with your tracking, adjust your intake accordingly. If fat loss is the goal, you can use a target rate of weight loss of 1% of body weight per week on average. If muscle gain is the goal, aim for about an average monthly weight gain of 1 pound. If after 2-4 weeks you’re actual rate of weight change is above or below the targets, adjust calorie intake up or down accordingly by 10% or so.
5. Rinse and repeat steps 3 & 4 until you a) reach your goal or b) your goals change.
The beauty of this concept is the lack or rigidity. You don’t need to have anxiety about whether your calorie intake is “right” or not. If your original estimation is inaccurate, the above process will uncover that fact and you’ll make the necessary adjustments over time to get on track. Remember, this isn’t a sprint… it’s a marathon.

One other note…

Considering the fact that 60-70% of Americans are overweight or obese, it’s reasonable to assume that most people reading this are interested in fat loss.

I’ve encountered many overweight clients who assume that because they’re fat, their metabolic rates are low. Why else would they be fat, right? If you matched them to a population of similar age, body composition, and everything else… sure, there might be some genetic variance in metabolic rate. Nothing massive… maybe 15% or so.

The fact is, the larger you are, the higher your energy costs actually are. You have more weight to move around and you have more tissue to maintain. Yes, even fat tissue has a metabolic cost. There’s no reason to set your calorie intake at 1,200 per day on the basis of having a “slow metabolism.” More often than not, such an extreme deficit* will lead to a lack of compliance. You don’t want to hop on the yo-yo diet train.

*Remember that 1,200 calories would be a large deficit for an obese person. Lighter folks have much lower daily energy costs, all things constant, and for some, 1,200 calories would not be unreasonable.

No comments:

Post a Comment