Can eating too little damage your metabolism and make weight loss harder?
Maybe you're working out consistently and eating healthy but you’re not losing weight (or not losing it as fast as you’d want).
Or you were losing weight consistently but now you’re stuck.
Or maybe losing weight was easier when you were younger but now with the same effort you struggle to get as lean as you would like. Does this mean that past diets or long-term low-calorie eating harmed your metabolism? No, not exactly. However, gaining and losing weight can change the way your brain regulates your weight. Here's how: You need a certain amount of energy (calories) to stay alive, as well as to move around. You can get this energy from food, or from stored energy (your fat tissue).
In theory, if you eat less energy than you expend, you should lose weight. If you do the opposite (i.e. eat more energy than you expend), you should gain weight. This post, let's focus on the "Energy Out" (burning calories) part of this equation. We burn calories in 4 different ways... 1. Resting Metabolic Rate (RMR):
RMR is the number of calories you burn each day just to breathe, think, and live. This represents roughly 60 percent of your calories burned each day. It depends on weight, body composition, sex, age, genetic predisposition, and possibly the bacterial population of your gut. A bigger body has a higher RMR.
2. Thermic Effect of Food (TEF):
TEF is the number of calories you burn by eating, digesting, and processing your food. This represents roughly 5-10 percent of your ‘energy out'.
In general, you’ll burn more calories in your effort to digest and absorb protein (20-30 percent of its calories) and carbs (5-6 percent) than you do fats (3 percent).
You'll burn more calories digesting minimally processed whole foods compared to highly processed foods.
3. Physical Activity (PA):
This is the number of calories you burn from purposeful exercise like working out at the gym, walking, biking, running, playing, gardening, etc.
4. Non-Exercise Activity Thermogenesis (NEAT):
NEAT is the calories you burn through fidgeting, staying upright, and all other physical activities except purposeful exercise. This varies from person to person and day to day.
Going back to eating too little...
When the 'energy in' goes down (i.e dieting), 'energy out' goes down to match it.
Thermic effect of food goes down because you’re eating less.
Resting metabolic rate goes down because you weigh less.
Calories burned through physical activity goes down since you weigh less.
Non-exercise activity thermogenesis goes down as you eat less.
Calories not absorbed goes down and you absorb more of what you eat.
You burn fewer calories because you are eating less. The opposite is also true. As 'energy in' goes up, 'energy out' goes up as well. Sometimes eating more can lead to more calories burned.
This is one way I am able to help my clients get stronger, leaner, and have more energy at the same time. By eating more of the right kind of food.
Next post, I'll cover the 'energy in' portion of this equation and when it would be beneficial for someone to eat less.
If all of this seems confusing, don't worry! At McNair Health and Fitness we make this seemingly complicated weight-loss equation, simple!
Our programs will give you the tools you need to feel and look your very best!
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Source: Can eating too little actually damage your metabolism? Exploring the truths and fallacies of ‘metabolic damage'. By Brian St. Pierre, MS, RD