# Build a bigger engine, not a smaller fuel tank

I made a big mistake the first time I attempted to lose weight. I obsessed over eating less, but I should have focused on building a body that requires more food to survive.

Measuring success by calories is like measuring success by how little fuel is left in your car’s tank. Your body is not a machine, but a dynamic system that adapts to abundance or deprivation. Run on low fuel for long enough and your body will adapt by downgrading its engine to conserve energy, losing significant horsepower in the process.

Running on low fuel is precarious. The moment you make a dieting mistake by accidentally filling up the whole tank, now you’re doubly screwed—not only is your tank (bodyfat reserves) completely full, you’re also stuck with a wimpy engine that will take forever to burn away the entire tank. This is a one way ticket to fatigue, stress, and depression.

Instead, it is more effective to focus on building a big, power-hungry engine.

A big engine has big benefits: if you accidentally eat too much, no big deal, a faster metabolism means you’ll burn off the extra calories in no time.1 This is a one way ticket to guilt-free ice cream, relaxed dieting, and boundless energy.

But you can’t just strap a rocket engine onto a Honda Civic to do a grocery run. A massive rocket surely consumes more fuel, but it only makes sense if your goal is to achieve orbital velocity when you turn the key.

Your body will build a larger engine (muscles) only if your labours are so demanding that your body is impelled to adapt by outputting more wattage.

Therefore, to build a big engine, maximize force production.

Force = Mass × Acceleration. Every workout, increase mass (the amount of weight you are lifting), or increase acceleration (how many reps and sets you are doing).2 This is the principle behind Linear Progression, which I outlined in more detail in a previous blog post.

Greater demands for force will trigger your body to develop ever larger engines required to output that force. Your body is highly efficient—your metabolism doesn’t increase unless it has a life-or-death reason to improve. Biology works this way because your metabolically wasteful ancestors were evolutionarily outcompeted by more resource-conserving rivals.

This means losing weight requires eating more food (fuel), not less, because you need to signal to your body that you have sufficient reserves required to run a high horsepower engine. But this only works if you have the discipline and commitment to building your engine, otherwise you’re just filling up the tank with empty calories.

Still, I think this journey is more rewarding than the opposite. Even if you fail, at least you’re left with a better engine, rather than a worse one, and engine upgrades tend to persist for a long time even if you’ve missed a few track days, whereas fuel levels fluctuate on a daily basis.

I think this principle applies to more than just dieting.

## Mental Model: Grow more instead of consuming less

Personal Finance: Once you’ve done the basic budgeting, it’s more effective to focus on earning more rather than spending less. You can only decrease your expenses by a finite amount, but there are no limits to how much you can increase your income. And building skills to raise your earning power tends to be permanent, whereas belt-tightening tends to be temporary.

Climate Change: Don’t admonish people to cut back on energy consumption. Instead, develop technology to massively increase power output from non-polluting sources. Solar panels tend to be permanent, but austerity tends to be temporary.

Non-Profits: Don’t try to minimize admin overhead; focus instead on delivering exponentially better results.3 This is the principle behind Effective Altruism. People will donate more if you demonstrate improved competency, more than enough to cover any inefficiencies.

Systems Thinking: Donella Meadows makes the point that the structure of flows is a more powerful leverage point than the capacity of a buffer. Faucets and drains influence water levels more than the size of your bathtub.

One caveat is that growth alone is not a panacea. Growing too fast can lead to catastrophic ruin. For the vast majority of people, the dieting advice I gave above is actually bad advice, because people tend to overeat and underexercise rather than the reverse, so following this strategy will lead you further from your weight loss goals. My personal psychology precludes this from happening in my specific situation, so you should consider how this tactic fits into your self-understanding. This advice is for me, not for you.

This is one of many lessons I learned while trying 21 different diet and exercise programs. Read more about 10 other big mistakes I made here: billmei.net/blog/fitness

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## Footnotes

1. Of course, if your fuel tank was extremely full to begin with, it can be good to focus on emptying it out for a while. Just know that a larger engine will empty it out faster.

2. $$\textrm{Acceleration} = \frac{\Delta \textrm{Distance}}{\Delta \textrm{Time}^2}$$. Distance = the total range of motion you are executing. The more reps and sets you do, the greater the total distance over which you are moving the weight. You can also increase force by moving faster (more explosively), i.e. decreasing $$\Delta \textrm{Time}^2$$; however, this is more difficult because there is a finite limit to how fast you can move, but you could exercise for an infinitely long distance.

Technically, we are actually maximizing Work (wattage) and not Force (newtons), and Work = Force × Distance ÷ Time, but increasing Work still requires you to increase distance or decrease time. But I presented Force first because people are more familiar with F = m·a than W = kg·m²·s⁻³

3. Minimizing administrative expenses can hurt you if better results can be achieved with highly salaried employees rather than itinerant volunteers. But tread carefully here, because volunteers can also be largely responsible for donations too.