If you’ve been stuck trying to figure out how to lose body fat, this is the no-fluff guide to getting to 12% BF — and staying that way.

THIS is what 30% body fat looks like.

Drop down to 20%, and in the right lighting, you might see some ab definition.

At 15%, your upper abs begin to show. 

But to really strip off the fat around your belly, you usually need to go even lower. 

At 12%, your six-pack finally pops, veins show in your arms, and the best part? It’s still maintainable and lets you enjoy life.

For me to get there from 15% body fat, it took six weeks.

To find out how long it’ll take you, find your current body-fat level in this lineup.

Go all-in and here’s how many weeks it’ll take.

And for women, here’s the equivalent.

But here’s the problem: based on a DEXA scan analysis of over 9,000 American men, less than 1% ever reach 12% or below. 

Your body is smart. Without the right plan, you’ll either get stuck early on … or end up regaining even more fat than you lost once the diet’s over. That's why learning how to lose fat strategically, not just quickly, is critical.

And it's also why I teamed up with five of the world’s smartest scientists and elite coaches to create a step-by-step plan that will show you how to lose body fat so you reach 12% and easily maintain it afterwards.

Let’s start with training. 

How To Lose Body Fat Without Losing Muscle: Smart Training Strategies

You Must Lift Weights

"Most people want leaner. They don't just want smaller. And when you lose weight without doing resistance training of some kind, then your probability of losing muscle as well as fat is almost 100%.”

That’s Dr. Mike Israetel, a well-known professor and bodybuilder with a PhD in sport physiology.

He explained that if you’re losing weight without lifting weights, or not lifting properly, then up to half of your “weight loss” can be muscle, rather than fat. 

This doesn’t just make you look “skinny” rather than “lean”, but it also causes your body to start fighting against you. 

"When you lose muscle, your body seems to have a special extra sensing ability to kick your hunger and cravings into higher gear than when you don't. Because if you lose a lot of muscle, your body's like, look, we got to regain."

Now, the other parts of this plan will help bring your muscle loss to 0, but your lifting routine is your biggest line of defense.

Light Weights, Higher Reps

And while the structure of your training won’t change much from your muscle-building phases, Dr. Mike suggests one important tweak: consider lighter weights for higher reps. This is crucial when you're figuring out how to lose body fat while keeping your strength intact.

"So putting a little bit more weight on the bar each time becomes less realistic in a fat loss phase, especially as you get deep into it.

Also, your ability to express your highest strength because you're underfed. Leveragers are getting worse in most cases, also reduces.

However, on the other hand, you have higher repetitions. Higher repetitions do burn a little bit higher calorie levels, but that doesn't matter much in the grand scheme because it's such a small amount total.

However, when you are in a fat loss phase, especially.

Towards the end, your endurance relative to your body mass typically goes up.

And so it turns out that you are not only better at higher rep lifting, but you can actually make some gains by adding repetition here or

And that psychological ability to add repetitions is like a big deal.

You're conserving muscle just as well as you would with heavier weights, but you get some progress, progress.

And that's a big deal. And this is a really, really low-key, super not important in the grand scheme difference, but it does count."

When To Switch?

Jeremy:

"And so when would you consider making that switch?"

Mike Israetel:

"Some people, all the way from 30% to 12%, would just train ultra well with whatever normal rep ranges they do, and it would never bite them in the ... Some people, anything below 25%, and their diet fatigue is already so high just from genetics or whatever, that like, oh, I really do need the higher reps to come rescue me.

I'd say the easiest recommendation I have is to continue training normally until you feel really fatigued and your strength is really starting to be like, ugh."

Optimal Workout Split?

But Dr. Mike’s take got me thinking; is there an “optimal” workout split for fat loss that most people are missing? 

Mike Israetel:

"If you're in a fat loss phase, as soon as you're not growing muscle, then you start losing it.

And then you come back and hit it again. You grow a little bit, but then you lose it again, and you can just continue to lose muscle that way over time.

Also, your ability to do really hard multi-set workouts is degraded substantially. Like a 20-set chest workout one day a week on a mass-gaining phase, you got your shake with you, you got your carbs, and you're good to go.

You can get through it. You're full of glycogen. But like those kinds of workouts just might be really, really tough.

And at the end of, you know, sets 15 through 20 on a fat loss phase, oh, you're doing sets all right, quote-unquote, but not a whole lot is happening.

So slightly more frequent workouts that make sure to hit the muscle, every muscle that you want to preserve maximally, two to three times a week on a fat loss phase."

Although there has yet to be direct research supporting Dr. Mike’s theory here, it does make sense — and the diets I’ve been able to preserve the most muscle with have always been those where I train each muscle multiple times a week.

Here are my favorite workout split options by the way, and you can get the full routines here:

• 3x/week: full body
• 4x/week: upper/lower
• 5x/week: u/l/p/p/l
• 6x/week: p/p/l/p/p/l

What About The Number Of Sets?

You've got workout split down. Now, if you're wondering how to lose body fat without sacrificing muscle, the number of sets you do can make all the difference.

A brand new study tried to find the answer, and I was even shocked by what they found.

Imagine 3 groups:

• Group 1 only diets.
• Group 2 follows the same diet but adds 2.5 hours of cardio per week, along with a 30-minute full-body workout once a week. 
• Group 3 doubles the workload — 5 hours of cardio and two 30-minute full-body workouts every week.

After 16 weeks, can you guess what happened?

Well, the diet‑only group dropped 15 pounds. 

Nice on paper, until you realize 40% of that weight came from muscle.

The second group lost 22 pounds, but 20% of it was still muscle.

The third group?

Same weight loss as group 2, but 100% of it was fat. 

No muscle loss. 

They even lost 50% more visceral belly fat. 

Now, there are two really interesting findings here:

First off, 2 short full-body workouts per week — just 6 hard sets per muscle — were enough to preserve muscle.

For chest, that’s just 3 sets of bench and 3 sets of flyes. Now, I’d argue that advanced lifters might want to aim for 6-10 weekly sets to be safe, but still, if you’re training hard, you need far less than you think to maintain your muscle mass. 

Second, although Group 3 performed twice as much cardio as Group 2, they didn’t lose more weight.

The researchers think the only reason they lost more fat was that the extra lifting day signaled their bodies to burn more fat rather than muscle. 

Which might lead you to wonder: does cardio really help when it comes to how to lose body fat?

It’s an important question, but before we dive into that, let’s get to the most crucial part of your plan: how to lose body fat through your diet to 12% BF.

How To Lose Body Fat Through Nutrition

"You can eat junk food and still lose weight and still lose body fat and maintain lean mass.”

That’s nutrition expert Layne Norton, a competitive bodybuilder and powerlifter with a PhD in Nutritional Sciences.

How To Think About Your Fat Loss Diet

He explained that the first step in setting up your weight loss diet is determining how much protein you should consume.

“I have a range I like to use, I tell people 1.8 to 2.8 grams per kilogram, if you're at the bottom end of that range, you're still getting enough protein that you're probably optimizing lean mass.

So once protein is set, you have to take those calories away because they're allotted the protein, and now you're left with carbohydrates and fats, and you can look at carbohydrates and fats as both are just sources of fuel, right?

And so what I tell people is I think the most important thing is picking a carbohydrate or fat breakdown that is easiest for you to adhere to, right?

If you're somebody who likes more savory things, a little bit lower carb, if you're somebody who likes a little bit more starches and sweet things, maybe a little bit higher carb, lower fat.”

Personally, I like a balanced approach.

I mostly get my fats from eggs, peanut butter, and olive oil.

Carbs are timed around my workouts: oats before, potatoes after, plus fruits and veggies throughout the day.

Protein is in every meal.

And because life without dessert isn’t a life I want, I finish the day with a sugar-free Ninja Creami made with my Built With Science protein, but if a donut jumps in my cart every now and then… I’m not complaining.

Should You Be Worried About Sugar?

Layne Norton:

"There was one study looking at over a hundred grams per day of sugar intake, like sucrose versus about 10 grams per day. The macros and calories were all exactly the same, and they were eating in a calorie deficit, and both groups lost the exact same amount of weight, exact same amount of body fat, and all their blood markers improved in both groups. 

So if you look at the science of body fat loss, if you're eating the appropriate amount of macros and calories, it doesn't really matter that much. 

You can eat junk food and still lose weight and still lose body fat and maintain lean mass. 

I'm a huge ice cream guy. I love ice cream. I have usually a small serving of ice cream almost every day.

So if you want to fit in some treats, it's okay, but if you want to be satiated, probably best to get the majority of it from minimally processed foods.”

One of the most overlooked parts of how to lose body fat is dialing in your calorie intake without going too low.

How To Lose Fat: How Many Calories Should You Eat?

Now with that in mind, let’s talk calories. Because you won’t lose fat if you’re eating more than your body needs.

However, eating too little can cause your body to start burning muscle instead.

To estimate how much you should eat, take your body weight in pounds and multiply it by 10 to 13.

You can use the lower end if you sit most of the day or are over 200 lbs, and the higher end if you’re active or lighter.

Here's a more advanced calculator you can use.

But remember — all calorie calculators are just rough estimates. It’s not uncommon for them to be off by 500 calories or more — the difference between losing fat or gaining it.

A far more accurate way to determine how many calories your body needs is to stick to a calorie target, track your weight daily, and aim to lose 1-2 pounds per week.

If your weight is dropping too slowly or too quickly, then you know it needs adjusting. 

Now my fitness app — which I’ll cover later — handles all of this for you automatically, and it can lock in your true calorie needs within just a couple of weeks, just like a coach would do.

But here’s the thing - after about 4 weeks of dieting, maybe 6 if you’re lucky — something strange starts to happen, which leaves people stuck right around 20% body fat. It’s not a motivation issue, it’s your metabolism fighting back — and in the next part of the plan, I’ll show you exactly how to beat it (ie., how to lose fat, continuously).

Metabolic Adaptation

"It's basically making all these subtle changes to reduce your energy expenditure and at the same time really jacking up hormones that are associated with hunger. And so basically the body is doing everything that it can to get you to eat more food and burn fewer calories."

That’s Dr. Eric Trexler, a Duke scientist and the Chief Science Officer behind our fitness app.

He explained how, almost immediately after you start dieting, your body fights back. 

"It's downregulating your resting energy expenditure and even your physical activity habits that you're not even thinking about. So changes in your postural control changes and the amount you fidget.

And to make things worse, as you get lighter, you’ll naturally burn fewer calories just by existing."

As a result of all these side effects, Dr. Trexler has found that for every 5% drop in body weight, your metabolism can slow by 100 to 200 calories per day.

So let’s say you start at 180 lbs and lose 10 lbs.

That means you might now be losing fat at half the rate you were at the beginning. Push it another 10 pounds, and fat loss might just stall completely.

How To Lose Fat (Continuously) By Fixing Metabolic Adaptation

The fix? 

It’s not complicated. Weigh yourself daily, track the weekly average, and if your weight stalls for two weeks, lower your calories by 100–150.

That was a key part of how I lost body fat going from 15% to 12%.

I started at 2,300 calories, but after four weeks, my app sensed my metabolism had adapted, so it lowered my target and kept me progressing.

But here’s the thing most people don’t realize when it comes to how to lose fat: eventually, your body hits a wall. 

And if you try to push through it, it’ll come back to bite you.

There's a right and wrong way when it comes to how to lose body fat — and I learned this the hard way.

One of my first diets, I went straight from 25% to 12% body fat. It worked — I lost 25 lbs in 16 weeks. But afterwards, I was starving and had the wildest cravings. I’d lie in bed at midnight thinking about donuts. And more nights than I want to admit, I’d get up, drive to the store, and inhale six in one sitting.

Within just a few weeks, I gained most of the weight back, and I honestly just felt like a failure. 

It turns out that I made a crucial mistake.

Don't Push Your Body Beyond What It Can Or Is Ready To Handle

Mike Israetel:

"So, like we have a little rule of thumb at RP, the hard rule is one phase, 10% body fat, no more.

A soft and probably much better rule is to aim for 5% in one phase before you go to maintenance.

And almost everyone thinks 5% is, my God, it's so doable and easy. And by the time they get to the end of it, they're like, whoa, this is actually a big change and kind of a lot.

And I definitely need a break. And the percent of successful people running in that 5% to 7% at a time phase before the maintenance is like, geez, I don't even know how much more likely they are to succeed."

So here’s the takeaway:

If you’re dieting, the maximum fat you should try to lose in one go is about 10% of your body weight.

For someone who weighs 180 lbs, that’s ~20 lbs, usually over 12–16 weeks.

After that, you have two options:

• Maintain your weight for at least 2–3 weeks, ideally longer.
  
• Alternatively, if you want to stay productive, consider transitioning into a lean bulk phase for a few months.

But don’t dive back into another cut until you’re actually ready.

If you’re still fantasizing about Twinkies and burritos, you’re not there yet.

I get that this might double your timeline based on what I showed you earlier. And believe me — if I hadn’t learned it the hard way, I would’ve ignored this advice too.

But I’d rather see you take twice as long and keep the fat off for good than end up right back where you started, like I did.

Now everything I’ve shown you so far can already help you get to about 15% body fat. However, to reach 12% and maintain it, there’s a powerful tool you need to be using.

Cardio. But not the way most people do it.

How To Lose Fat With Cardio

“So if you're thinking, oh I'm going to use my wearable device or I'm going to look at what's burned on the cardio machine, or I'll use some estimation. Oh, I'd burn 300 calories. Awesome. That's going to add 300 to my daily deficit. That's not the case.”

That’s Dr. Eric Helms, pro bodybuilder and publisher of over 160 research studies. 

Eric explained that your total daily calorie burn doesn’t directly increase with more exercise as you might expect. This is known as the constrained energy model.

When you do more cardio — especially while dieting — your body finds sneaky ways to offset it:

• You fidget less
  
• You subconsciously move less
  
• And oftentimes tou get hungrier and eat more
  

So even if your cardio session technically burns an extra 300 calories, by the end of the day this could go down to just 150, or even less.

And that’s exactly what researchers found in the study we mentioned earlier — where participants doubled their cardio… yet didn’t lose any extra weight.

But don’t write off cardio just yet; it's a key tool if you want to master how to lose body fat the smart way.

It’s a key tool for achieving 12% body fat; you just have to use it properly. 

Dr. Eric Helms:

"You want to let the diet do most of the work of fat loss for you.

But there is a benefit in being active when it comes to appetite regulation as well as weight management later on.

And also, it gives you a little bit more buffer room in terms of your energy intake when dieting. So what I recommend people do is if their step count is under 7 to 9000 per day, then you absolutely should.

When you start dieting, you want to get into that range, or the diet is going to be hard because your appetite is probably already a little bit dysregulated."

The Big Takeaway

If you're still not sure what to do when it comes to how to lose fat, here's a simple checklist:

• First, set your baseline. If you’re getting fewer than 7–9k steps per day, fix that. That alone can make your diet feel much easier.
  
• Next, if you’re already in that step range, try setting a goal of adding about 3000 to 5000 more steps to your day up to a max of 15,000. Or, if you can’t commit to steps, you can layer in 2–3 short cardio sessions per week — just 30 minutes each.
  
• Finally, stay consistent and only once your fat loss stalls, use what Eric calls the 80% rule

80% of the time, reduce calories. Save cardio increases only when dropping calories becomes unsustainable.

Now at this point you have to be really careful. You have the perfect plan on paper but there’s one thing that can still stop you from ever reaching 12% body fat. 

Your mind.

Psychology

"It's not always just about that meal. It's also about what are the other things around it that are affecting it."

That’s Laurin Conlin, a researcher and coach who, through her years of experience, found 3 mind traps that keep people in the cycle of losing fat, only to regain even more.

Mind Trap 1: Treat Meals

The first has to do with treat meals. 

"If it's Tuesday or Wednesday and all the coworkers are going to lunch at the same spot you guys always go to, kind of has decent halfway shitty bar food. Do you really like need to eat that?

Like probably not.

Like you're probably not even excited to really have that. If you're somewhere in somebody brought like store bought like treats, you know, is that really as exciting? Like, probably not. If it's the holidays or you're at a party and someone made their like, the like and then, cookies that are like your favorite, like, yeah, I want you to have 1 or 2 of those.

I don't want you to have the stale like office cookies. I want you to have that, if you are going on a date night with your significant other and you're like, oh my gosh, this place has amazing cocktails. And, you know, that's such a good vibe. And I want to have this, and oh, look at this. Enjoy that.

And most people have generally something social that is like an enjoyable social thing that they can like look over to maybe once a week. And there's probably a few other things like food wise during the week, that maybe they could probably say no to.

It's about looking at things in the bigger picture and not just being so like myopic like what is right in front of me. Okay, what is the rest of my week probably going to look like?"

But let’s say Saturday night you know it’s a “worth it” dinner out for you.

Mind Trap 2: Guilt

Lauren has found there’s a second big mistake people make beforehand that can sabotage weeks of progress. 

"So let's say someone has that Saturday dinner and they have the best intentions, but they want to say, okay, I know it's going to be a lot of calories.

So like, let me just like really, really restrict during the day. So you go to this dinner and then you're like, oh my gosh, well, I'm going to order this drink that I really wanted.

Oh, we're going to have appetizers like, yeah. And now things you're like, well I haven't really eaten all day. So like I can just have this. No. And then maybe go home, maybe overeat at that and maybe have a few too many drinks. Don't really feel too great the next day. Feel bad about what was consumed.

So then what happens? Maybe don't train, maybe don't eat healthy that next day. And like so this is where things snowball. Or people maybe get into this behavior mentally where they're like, I need to overcompensate now. Well, because I did this. Now let me go walk a bunch and do extra cardio. And that really never proved to be effective either, because it just creates this big cycle of like up and down, up and down.

If you make a decision, go for it. I want you to own it. Even if it was, you know, quote unquote, not on the plan, but you made that decision in that moment that you wanted to do that. That's fine. I'd rather you own that, because then you can say, you know what?

I did enjoy that. And that was worth it. What happens is most people don't do that. So then they but they still do it and then they feel bad. And then that guilt is what creates that cycle. And it's really, really hard to get out of that. So yes, having like still standard kind of meals that would be similar during the day, not under eating, going into it.

And then. Yeah, really making that decision."

Mind Trap 3: Trying To "Hack" Hunger

But perhaps the most powerful psychological fix her clients make has to do with hunger.

"Can I tweak this thing? Can I hack that? Can I get around?

It becomes this obsessive focus that like, honestly magnifies it.

So, outside of doing all the things that can help manage hunger, recognizing that it is probably going to be a part of your diet and just accepting that it's there is one of the best strategies."

TL;DR

• To reach 12% body fat, you need a sustainable plan, not just calorie cuts. Understanding how to lose body fat means combining smart training, strategic nutrition, and mindset work.
• Train to keep muscle, not just burn calories. Lifting weights 2–3x per week per muscle group — even with fewer sets — helps preserve strength and prevents the “skinny fat” look.
• Use cardio strategically. Cardio helps regulate appetite and energy balance, but it’s not the main driver of fat loss. Walk 7–9k steps daily, then layer in 2–3 short sessions only when needed.
• Dial in your nutrition first. Figure out your ideal protein intake, then adjust carbs and fats based on what’s easiest to stick to. That’s the real key to how to lose body fat with consistency.
• Watch out for metabolic slowdown. As your weight drops, your metabolism adapts. Monitor weekly averages and adjust calories gradually to stay in fat-burning mode.
• Psychology matters more than people think. The way you handle cravings, guilt, and social eating plays a huge role in whether your fat loss sticks or rebounds.

Before You Go ...

But here’s what most people don’t realize: how your hunger changes can reveal what level of body fat is actually sustainable for you.

Some people — like myself — have an easier time getting lean, while others are naturally better at gaining size.

Very few are gifted at both.

So if you already feel miserable well before 12%, realize you can still look incredible at a higher body fat, especially if you’ve taken the time to build muscle and properly train your abs to make them pop more.

And for the only 2 ab exercises you need to do just that, check out this article next.

But if you want a full science-backed system that puts everything we’ve talked about into one personalized plan — from workouts, to nutrition, to motivation — try 2 weeks free of my new app here:

Click the button below to try the BWS+ app for 2 weeks, for free, no strings attached:

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Thanks so much for sticking to the end, and I’ll see you next time!