In last week’s blog post we looked at how some of my blood markers have changed since cutting weight at the beginning of 2023 to November of 2023. At the end of that post I mentioned that I think some of the changes in my blood work were due to what is referred to as low energy availability or LEA for short. In part two of this series on the cost of weight loss we will look into the impact of LEA and how it is impacting my metabolism.
Essentially you can think of LEA as a state in which the body is not given enough energy to maintain everything it needs to run optimally. Your body has to make a hard choice, it needs enough energy for critical functions (think of things like your organs functioning properly) plus it will need enough energy to power your muscles for whatever physical demands you require of your body. If there is not enough energy left over to produce sex hormones or thyroid hormones for example, your body says “Oh well you can survive without them!”
When you hear people say weight loss slows your metabolism this is exactly what they are talking about. Your body starts to become very efficient with its caloric expenditure. At first it might just make you more fatigued so you move less, but the lower your calories go, the more drastic the measures it needs to take. If it has to it will stop spending energy on hormone production, hence why in my blood work you see lower thyroid hormones and lower testosterone.
In very extreme cases where calories are really low for a long period of time you can see thinning of hair, brittle nails, weaker bones…these are your body’s last ditch attempt at conserving calories.
All of these things, from producing hormones, to movement, to maintaining healthy bones, fall under what is called our metabolic rate. As your body starts to conserve energy, because you are dieting, it will cut back on hormone production, your desire to move will go down, your body will allocate less resources towards bone formation and maintenance. By doing all these things your body is slowing your metabolism.
We can see my metabolic rate has slowed by comparing my current resting metabolic rate done in October 2023 (while eating 2000+ calories a day) to one from February 2023 (when eating 3000+ calories a day).
In February of 2023 according to my resting metabolic test I was burning 2201 calories at rest of which 73% was composed of fats and 27% was composed of carbohydrates. When compared to other males my age I was in the top 75 percentile for metabolic rate, meaning I was burning more calories than the average male my age.
In October of 2023 I repeated the test. In that test I was burning 1730 calories at rest of which 83% were fats and 17% were carbohydrates. When compared to other males my age I was only in the top 55 percent for my metabolic rate, just barely above the average metabolic rate.
I am not saying that the results from October are bad, they are just lower than in February.
My slower metabolic rate is not surprising and lines up with what we see in my blood work from last week’s post. The lower thyroid levels have the side effect of lowering your metabolic rate (Brent, n.d.). My body is basically trying to slow my metabolism down to balance out my energy expenditure and energy intake.
This is what is commonly referred to as metabolic adaptation and is a well documented side effect of being in a caloric deficit. You may have even heard of metabolic adaptation before. It is mostly used in order to instill fear in people and suggest they have somehow “damaged their metabolism”. In reality the body is doing exactly what it would need to do to survive 100s of thousands of years ago when we would sometimes have to survive on very little food for an extended period of time. In nearly all cases once you begin eating enough calories again nearly all metabolic adaptation is reversed.
So the question for me in my situation is what amount of calories would I need to eat to reverse these adaptations. Luckily the research behind LEA can help me get a basic idea of how much I should be eating. We can actually calculate our energy availability. The cut offs for energy availability are below.
The sweet spot for energy availability is between 40-45 cal/kg fat-free mass.
The formula to calculate energy availability is
Average Daily Caloric Intake – Average Daily Energy Expenditure / Lean Body Mass = EA
My average daily caloric intake is 2000 calories a day.
To figure out my average daily energy expenditure we need to find out my total energy expenditure. We know my resting energy expenditure from my resting metabolic rate test so now we just need to figure out how much I am expending during my other daily activities.
First look at exercise. My typical week of exercise looks like this:
Monday: Strength Training for 70 minutes
Tuesday: Rowing at a moderate intensity for 20 minutes and a easy run for 30 minutes
Wednesday: Strength Training for 70 minutes
Thursday: Run at a moderate intensity for 50 minutes
Friday: Intervals on the rower and strength training for 30 minutes
Saturday: Strength Training for 70 minutes
Sunday: Rest day
To get an idea of how many calories I might expend during these activities we can use this online calculator. It won’t be perfect but it will be good enough for this rough estimate.
Monday: 411 calories
Tuesday: 405 (running) + 164 (rowing) = 571 calories
Wednesday: 411 calories
Thursday: 675 calories
Friday: 169 (rowing) + 176 (strength training) = 345 calories
Saturday: 411 calories
Sunday: 0 calories
My total exercise calories for the week would be 2824 calories. If we divide that by 7 we would get my average exercise calories for the week which is 403 calories per day. If we add that to my resting energy expenditure of 1730 calories we get 2133 calories.
Now we just need my lean body mass. I have that from my DEXA scan, which we will look at in the next blog post. According to my DEXA scan in November of 2023 I had 59 kilograms of lean body mass.
We now have everything we need to calculate my energy availability
(2000 – 403) / 59 = 27 calories/kg fat-free mass
So as we can see, based on the thresholds from the chart above I am in a low energy availability state.
Now say I wanted to get to a healthy energy availability of 43 calories/kg fat-free mass, how much would I need to eat?
We can use the same formula but solve for calories…
(Calories/kg fat-free mass * lean body mass) + average daily energy expenditure = average daily caloric intake
Let’s plug in the numbers…
(43 * 59) + 403 = 2940 calories
I would need to eat roughly 3000 calories to get to a point where I have decent energy availability. Ironically this is about what I was eating in January and February when my blood work looked better and my resting metabolic rate was higher.
You might be saying to yourself, this is all fascinating (maybe not the math) but how does this apply to me?
Most people don’t need to worry about being in a low energy availability state, but there are 2 very important takeaways for everyone reading this post.
- Metabolic adaptation is real, it will happen as you decrease your calories and lose weight. However it is not to be feared, you did not break yourself, and it can be reversed in most situations as you return to maintenance calories.
- This is the most important takeaway…I was not struggling and suffering eating this way. In fact I was relatively satisfied most days and could eat like this happily for a long period of time. This is important because, if you want to lose weight, this is the holy grail of weight loss.
If you are wondering what my meals looked like to maintain my body composition at this caloric intake, luckily for you I documented that as well! Here is the breakdown of how I was eating.
Breakfast
3 eggs, ¼ cottage cheese, 1.1 ounces smoked salmon, a large amount of veggies sauteed, 1 tbsp guacamole, hot sauce, ¼ cup Birch Benders Paleo Pancake mix, 96 grams of banana, 13g of Magic Spoon cereal
Lunch
10g of smoked oysters, 10g of beef liver, 3.6 ounces of chicken, pickles, kimchi, a tomato cucumbers, roasted veggies from the night before, ½ cup blueberries, 3oz strawberries, 100g of Simply Delish Banana Pudding, some chocolate LMNT sprinkles on top of the pudding
Dinner
4 oz top sirloin, steamed broccoli, grilled eggplant, 150g of butternut squash with salt and cinnamon
Dessert
80 grams of homemade vanilla ice cream (made from 2 tbsp Simply Delish Vanilla pudding, 1.75 cups of almond milk, 2 scoops of Legion Vanilla Whey Protein Powder), 6 grams Magic Spoon cereal, 1 Siete Mexican Chocolate Cookie.
As you can see I wasn’t eating a small volume of food, I wasn’t restricting one specific macronutrient and I wasn’t skipping one or two meals. I was eating 3 balanced meals a day plus a small dessert.
You do not need to struggle and suffer in order to lose weight. You also don’t need to be eating a small amount of food to be undereating. The one thing you will notice about the meals I am eating is that they are all based around protein and vegetables with a moderate amount of fruit in the mix. This is an illustration of exactly why I say if you are interested in optimizing your body composition, the best thing you can do is eat mostly whole foods. It doesn’t need to be 100% whole foods, as you can see I eat some processed foods as well, but most of what I eat is whole foods. It is hard to not feel full and overeat when you eat this way. You can eat a lot of food for very little calories.
Am I telling you that you should eat just like me?
No.
What I want you to take away from this blog post is that weight loss and reaching your optimal body composition does not need to be hard, you do not need to be on the struggle bus. You can eat 3 meals a day, you can have fruit, you can eat a lot of veggies…hell you can even have dessert and get to a healthy body composition! However to do that you probably need to be eating primarily whole foods as I am. The more processed foods you try to include in your diet, the less full you will feel, the more accurate you will have to be tracking your food intake you will need to be, and it could be harder to hit micronutrient goals (processed foods are generally micronutrient poor and you are already consuming less food due to your caloric deficit). In general the more processed foods in your diet, the more it will feel like you are on the dieting struggle bus.
But what about my apparent metabolic adaptation? Can that be avoided? If not, is there anything we can do to mitigate any adaptation so that the impacts are as small as possible?
The answer to those questions will come in my next blog post. To be the first to know when that is posted sign up for my newsletter using the form below and I will email you as soon as it is available!
References
Brent, G. A. (n.d.). Thyroid hormone regulation of metabolism. PubMed. Retrieved November 22, 2023, from https://pubmed.ncbi.nlm.nih.gov/24692351/
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