Over years of working with training and nutrition clients, there are a handful of questions I get asked over and over again that have pretty basic answers. Unfortunately, due to all the exercise and nutrition misinformation out there, a lot of people stay in the dark.
- What exactly is a calorie?
- What are “macros” and how much of them do I need?
- What is the deal with protein?
- How do I keep my metabolism “healthy”?
I’ve gone into great detail on most of these topics in previous posts, but we still need a basic rundown of what our metabolism is and to dispel one of the big the myths surrounding it.
To start, ‘metabolism’ simply means “sum of chemical reactions in an organism." From there we have ‘anabolism’-chemical reactions synthesizing larger molecules from smaller ones (in other words building muscle mass or simply growing in general) and ‘catabolism’-chemical reactions breaking down large molecules into smaller ones (for most practical instances, using energy stores up, hopefully in the form of fat). I’m not going to get into a bunch of science jargon here, but there is obviously a lot going on when we eat and digest food and build muscle/store fat during anabolism. On the other end, there are four very distinct ways we use energy in catabolism:
1. Basal Metabolic Rate (BMR)
BMR is by definition the energy we need to keep our body running by performing the most basic vital functions- brain activity, heart pumping, breathing, maintaining a consistent body temperature, etc. This accounts for the majority of most of the calories your body uses on a daily basis.
2. Non-Exercise Activity Thermogenesis (NEAT)
This is all the physical activity you do during the day that is not planned exercise. Walking around, texting on your phone, fidgeting, talking, etc. This is honestly the kicker when it comes to weight loss, more on that later.
There is obviously a large degree of variation here depending on what kind of exercise you participate in, but unless your workouts are consistently several hours long at a pretty high intensity, you’ll burn more calories from NEAT on a daily basis than exercising.
4. Thermic Effect of Feeding (TEF)
Digesting food and sending it to the right place in our bodies also requires energy. About 25-30% of the protein calories you consume are required for TEF, compared to about 2-7% for carbs and fats.
The biggest myth I hear repeated all the time is that there is a state called “starvation mode” in which when you cut down to a certain number of calories that your body will suddenly drop its metabolism and make it impossible to lose any more weight, or even gain weight. This idea is echoed by many people who cut their calories, lose some weight, cut them again, and then weight loss stalls, making it seem like this is in a fact a real thing.
If you are trying to lose weight, you are always better off doing it slowly and consistently for the following reasons:
When you reduce calories drastically (like going from eating whatever you want for months/years to following a strict elimination diet or cutting calories in half) your body will turn on its defense mechanisms. As we learned in elementary school biology, living organisms like to stay in homeostasis, therefore a sudden threat that we are going to starve can trigger some hormones to increase or decrease, which can have some minor impact on BMR.
However the far bigger hit will come to NEAT. If you are suddenly consuming a lot less food, your subconscious will actually start causing you to conserve energy by making minor decreases to your day-to-day movements. I experience this personally any time I’ve dieted down for a bodybuilding show. I’m usually a high-energy, type A person who is practically running around the gym, walking very quickly, and fidgeting non-stop when I’m sitting down.
But at a certain level of leanness, all of this slows down or stops. If you were exercising before you start your crash diet, it will be impossible to keep up the intensity in the gym, so you will likely not work as hard or burn more calories there. Your strength might even decrease, and then you may begin to lose muscle mass.
Finally, you’re eating less food, so your TEF is down as well. To make things even worse, it's simply not sustainable following a diet like this. So even if you manage to keep your activity levels up and keep training hard, the chances that you’ll have a lapse in willpower at the end of the night and go on a cookie binge are now exponentially higher.
While there is nothing such as “starvation mode,” all these drops in various facets of metabolism can add up to quite a significantly fewer amount of calories being expended each day. Unfortunately, this is the way most people tend to diet, and also why “diets” have such a low success rate when looking at the course of a year or over several years. But don’t worry: there are lots of ways you can get into a calorie deficit and still consistently lose weight.
I suggest a 1% weight loss of total body weight per week as a good maximum; more than this and you might start to run into the above problems.
I also recommend making a point to be aware of your NEAT, so start looking for ways to add some activity into your day. That could be walking places close by or adding a daily morning or evening walk, parking farther from the office, or even standing by the bar instead of slouched in a barstool sipping your drink. These may all seem like trivial changes, but they add up in a big way.
Keeping your calories higher and going for weight loss in the long run vs wanting to see instant gratification on the scale will ensure that your workouts don't suffer, you don't give into cravings, and set you up for sustainable weight loss long term. After you’ve dieted for 6-10 weeks, and you’ve (hopefully) lost some weight, it's a great idea to bring calories back up to maintenance and pause for a bit at this new weight before dieting again. While you will burn slightly less moving your lighter self around, you'll also probably find you have more energy to be more active. If you repeat this process over the course of months or years, you’ll realize that traditional “dieting” doesn't really make much sense.
Metabolism is a very nuanced topic, but hopefully this covered most of your questions. As always, don't hesitate to leave a comment, and let me know any other nutrition topics you would like to read about!