Why you should maximize your metabolism to optimize fat loss

Mar 3, 2023

Losing weight is simple in theory: just eat fewer calories than you burn. But simplicity doesn’t imply ease. Cutting calories can be a grind with a sluggish metabolism. Because the less you burn, the less you can eat.

Even if you start dieting with a decent metabolism, over time you’re bound to see some slowing. And when your metabolism reaches rock bottom, it’s hard to limit your food intake sufficiently while still feeling satiated. Continuing and sustaining such weight loss becomes a herculean effort that often ends in vain.

So if you really want to lose fat forever successfully, you’ll need to rev up your metabolism. Keep reading to learn both why and how you should maximize your metabolism to optimize fat loss.

Why metabolism matters for fat loss

Creating a calorie deficit

Weight loss is fundamentally driven by a calorie deficit. That is, you need to take in less energy than you’re expending. When you’ve got a roaring metabolism, cutting calories is far easier than when your metabolism moves at snail speed.

For example…

Imagine two people want to lose weight, so they drop their calorie intake by 500 calories. They’re identical in every way except for their metabolism.

Person A burns 3,000 calories daily, whereas Person B burns only 1,500 calories.

Since Person A has a high metabolism to start, cutting out 500 calories drops their calorie intake by 17%.
Person B, on the other hand, must drop their calorie intake by a whopping 33% to lose the same amount of weight!

Although they’re both cutting the same number of calories, 500 calories seems like a lot more when you’re eating fewer calories to start.

Cutting calories is relative. The slower your metabolism, the more you’ll notice the calorie deficit. When you’re eating little to begin with, further limiting your food intake can feel like fasting.

Metabolic adaptation

Even if you start a weight loss phase with a reasonably high metabolism, you’ll find it gradually slows the longer you diet - a phenomenon called metabolic adaptation. As a result, you’ll have to cut calories more and more to continue losing weight.

Metabolic adaptation is a protective mechanism that your body deploys to ensure your survival (i.e., to prevent you from starving to death). While beneficial during times of famine, such a safeguard is more of a hindrance than help to the modern dieter.

These widespread adaptations result in reductions in all aspects of total daily energy expenditure (TDEE), such as…

Non-exercise activity thermogenesis (NEAT)

‍NEAT refers to incidental, non-exercise-related movements, like fidgeting, doing housework, and walking. Of all components of TDEE, NEAT is the most variable, ranging from ~100 to 800 calories daily and is influenced by numerous factors - from occupation to energy balance^{(1, 2)}. Specifically, simply being in a calorie deficit causes unconscious reductions in NEAT^{(3, 4)}.

Exercise activity thermogenesis (EAT)

‍When you’re in a deficit, you tend to burn less energy during exercise for a variety of reasons…

Your body becomes more energetically efficient during exercise⁽⁵⁾.
Weight loss makes exercise itself easier, since you have less mass to move.
Continually practicing the same form of exercise allows your body to become more mechanically efficient - so you’re less wasteful with energy during your workout⁽⁶⁾.

What’s more, when you increase exercise to burn more calories, your body actually compensates by further reducing NEAT⁽⁷⁾!

Resting metabolic rate (RMR)

‍RMR refers to the energy needed simply to survive at rest. Your body mass (i.e., organs, muscle, and fat) plays a significant role in your RMR - so weight loss predictably reduces RMR. However, RMR actually decreases beyond what you’d predict due to lower levels of hormones like leptin, insulin, thyroid hormone, estrogen, and testosterone^{(8, 9, 10, 11)}.

Thermic effect of feeding (TEF)

‍The food you eat influences your energy expenditure as well: TEF refers to the amount of energy required to digest and absorb macronutrients. Your TEF naturally lowers during a calorie deficit, since you’re consuming fewer calories.

Fortunately, you aren’t fated to fail your diet due to metabolic adaptation. The right strategies can help you maximize your metabolism, so you lose fat without severely slashing calories.

How to maximize your metabolism to optimize fat loss

Eat a high-protein diet

‍Consuming sufficient protein is crucial for preserving muscle mass during a diet. And muscle is a metabolically expensive tissue: one pound of muscle burns approximately 6 calories daily, compared to 2 calories per pound of fat⁽¹²⁾. Consequently, preserving muscle helps keep your RMR high despite a calorie deficit. Moreover, protein has the highest TEF of all the macronutrients, since approximately 20-30% of your calories from protein are spent simply digesting it⁽¹³⁾! Protein also has the bonus benefit of supporting satiety, to help you feel fuller on fewer calories^{(14, 15)}. Aim to get ~1 gram of protein per pound of lean body mass daily.

Some good protein sources include…

Lean meat
Eggs and egg whites
Fish
Greek yogurt and cottage cheese
Low-fat cheese
Quality protein powder
Soy products (i.e., tofu, tempeh, edamame)

Resistance train

‍Alongside protein, resistance training provides a potent stimulus for muscle preservation when you’re dieting⁽¹⁶⁾. What’s more, resistance training seems to enhance resting energy expenditure independent of muscle gain⁽¹⁷⁾.

To best boost energy expenditure and preserve muscle, train each body part at least twice weekly, with a focus on compound lifts, including variations of…

Squats
Deadlifts
Vertical presses (i.e., overhead press)
Vertical pulling (i.e., lat pulldown or pull-ups)
Horizontal presses (i.e., bench press)
Horizontal pulling (i.e., rows)

Resistance training for weight loss is programmed no differently than resistance training for maintenance or gaining: use proper form, push yourself, and strive to get stronger over time.

Get quality sleep

‍Poor sleep can exacerbate the effects of metabolic adaptation and increase the risk of muscle loss. In fact, one study found that individuals in a calorie deficit lost 55% less fat and 60% more muscle over 2 weeks when sleeping only 5.5 hours compared to 8 hours⁽¹⁸⁾. So, although you can lose weight while sleep-deprived, the weight you lose contains more muscle and less fat! Try to get 7-9 hours of quality sleep to support muscle preservation and keep your RMR reasonably high.‍

Reduce stress

‍Similar to sleep, chronic stress can impair your metabolism by increasing the risk of muscle loss⁽¹⁹⁾. In addition, chronic stress may also lower resting energy expenditure by suppressing thyroid hormone, sex hormones, and leptin while increasing ghrelin - thus exacerbating the effects of metabolic adaptation^{(20, 21, 22, 23)}.

To reduce stress levels, practice regular relaxation and self-care, such as…

Meditation
Breath work
Journaling
Nature walks
Massage
Mindfulness

Avoid extreme or prolonged calorie deficits

‍Extreme calorie deficits result in rapid weight loss, which increases the risk of muscle loss and its associated drop in RMR^{(24, 25)}. Moreover, staying in a calorie deficit for too long can elicit pronounced metabolic adaptation. So seek a balance, in which you don’t lose weight too quickly but also aren’t stuck dieting forever. Generally, limiting your rate of weight loss to ~1 pound per week will best maintain your muscle and metabolism. And after completing your weight loss phase, return to maintenance calories for at least the same amount of time you spent dieting.

Increase your daily movement

‍To counteract lower levels of NEAT and EAT that occur when losing weight, monitor your activity levels and increase them as needed. Specifically, you can track your daily steps to ensure they don’t dip along with your calorie intake.

You can sneak in some extra activity by…

Taking a short post-meal walk.
Walking during phone calls.
Taking the stairs over the elevator.
Parking farther away from the store.
Cleaning and doing yard work.
Engaging in physically active hobbies (i.e., gardening, recreational sports).
Taking your kids outdoors to play.

And while the fat-burning benefits of intentional cardio are overrated, adding in a session or two can help when you’ve hit a weight loss plateau. However, be sure to implement cardio sparingly to minimize its accompanying metabolic adaptations. In particular, start off with just one weekly workout and ramp up as needed.

What to do when your metabolism seems beyond repair?

If you’ve already dieted too much, too hard, or too long, you might find your metabolism is too low to sustain. In this case, you’ll need to build your metabolism back up before re-entering a weight loss phase. Luckily, following a reverse diet can mend your metabolism while minimizing fat gain.

With a reverse diet, you slowly increase your calorie intake, creating a small surplus to which your body gradually adapts. Step by step, each small surplus becomes your new maintenance calories as your metabolism progressively rises. Once you’ve reached a more sustainable metabolic rate, you can return to maintenance or start a new weight loss phase depending on your goals.

The wrap-up on metabolism & weight loss: burn more or burn out

Your metabolism can make a world of difference when it comes to weight loss.

The slower your metabolism, the less you can eat and still shed fat. And when you’re stuck eating too little, you’re apt to feel more hungry than happy.

Luckily, you don’t have to settle for a sluggish metabolism or starve yourself to lose weight.

With the proper strategies, you can speed up your metabolism and set yourself up for both successful and sustainable fat loss.

With a faster metabolism, cutting calories feels much more doable.

So get your body to burn more - and you’ll never burn out.

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