How to Lose Fat Quickly (12lb in 90 days)

Losing fat can be frustrating when you can’t seem to lose fat even though you don’t eat a lot.

It’s tempting to start blaming your metabolism or genetics when nothing seems to work.

But losing fat is easy.

In fact, you can quickly lose 1lb of fat per week – without starving yourself, without spending 6 days a week in the gym, and without doing cardio.

In this guide I’m going to show you how to lose fat fast and permanently. I’m going to bust through popular myths about fat loss, and answer popular questions on how to lose fat.

But first, I’m going to tell you exactly why you haven’t been able to lose fat.

Let’s go.

Why You Can’t Lose Fat

You underestimate How Much You Eat

If you can’t lose fat, it’s because you’re eating too much.

You probably think yo don’t eat a lot. But you are. Otherwise you wouldn’t be struggling to lose fat.

Maybe you “eat healthy”. But that doesn’t matter either. If your “healthy diet” doesn’t create a caloric deficit, you will not lose fat.

The truth is that most people are terrible at estimating how many calories they eat a day.

They dramatically underestimate how much they really eat.

Here’s proof: track how many calories you eat per day for a week using an app like Myfitnesspal.

A lot of people end up shocked to discover that some of their favorite foods that they think were “healthy” contain tons of calories.

Those excess calories are what are keeping you fat.

You Overestimate How Much You Burn

Cardio is a waste of time for most people.

An hour on the treadmill usually burns about 500 calories.

That’s the equivalent of one big mac (without the fries and coke) or one “Frappuccino” at Starbucks (without the cake or muffin).

So you can easily undo that hour of cardio by just eating one high calorie meal or drink.

And yet many guys think they can eat whatever they want because they do an hour of cardio each day.

You can’t.

Cardio is only going to burn a lot of calories if you can spend several hours in the gym each day.

If you can train like an athlete, then you can eat whatever you want without getting fat.

But I don’t think you have the time to train that much.

You’re therefore going to have to watch what you eat.

Otherwise you won’t lose fat.

You’re Not Eating Enough Calories

If eating 500kcal per day less makes you lose 1lb of fat per week… then eating 1000kcal/day less must be even better, right?


The more fat you lose, the more you need to further reduce your daily caloric intake to continue to lose fat.

If you reduce your calories by 1000kcal/day from week one, what are you going to do when you’re no more losing fat on that?

Besides nobody can stick to low calorie, 1200kcal/day diets long-term.

No matter how much willpower you have, eventually you’ll get hungry and binge.

That’s how tons of people end up gaining all the weight they lost back (plus more).

More isn’t better when it comes to losing fat.

You Waste Your Time Eating Healthy

Now I eat healthy, and recommend you eat healthy too.

But eating healthy doesn’t guarantee you’ll lose fat.

In fact, there’s John Cisna who lost 37lb while eating McDonald’s three times a week for 90 days.

There’s also Mark Haub, professor of nutrition in Kansas. He lost 27lb in 10 weeks eating mostly twinkles (even his bad cholesterol and triglycerides dropped).


That would be stupid.

My point is: it’s not how “healthy” the food is, it’s how many calories there’s inside.

Because many “healthy foods” are in fact high calories.

Consider this:

  • Smoothies and fruit juices are healthy because they have a lot of vitamins. But they’re also concentrated sugars. Minute maid Apple Juice has just as much sugars as Coca-cola.
  • Salad is healthy, and a low calorie food. But restaurants often add high calorie dressing, croutons, guacamole, etc .McDonald’s salads often have more calories than a big mac.
  • Dried fruits and nuts are healthy. But they’re calorie dense. 20 dried prunes has about 500calories – the same amount of calories as one big mac again.
  • Organic food may be healthy. But an “organic donut” is still a donut. It doesn’t matter if the sugar and fat is from an organic source. It’s high calorie

Eating healthy is good. I do it, and recommend it.

But to lose fat, eating healthy isn’t enough.

Eat Less Calories Than You Burn to Lose Fat

It’s that simple.

If you’re not losing fat, you’re not eating less calories than your body burns.

It doesn’t matter if you eat healthy, that won’t make you lose weight unless you;re total caloric intake is lower than what you burn.

Maybe you are eating less than last month. But if your calorie intake is still higher than what you burn, you still won’t lose fat.

You have to create a caloric deficit, and you do that by eating less calories than your body burns.

Start Tracking Your Calorie Intake

You need to become aware of how many calories are in the most common foods you eat.

There are foods you eat, that are maybe healthy, or that you think are not so bad, but that in are high in calories.

Think of the Pareto rule

  • 80% of your results come from 20% of what you do
  • Most people eat the same foods 80% of the time

Therefore, there are foods you tend to eat a lot, but that are probably damaging your fat loss.

But you don’t know about it.

So start tracking everything you eat for one month using an app like myfitnesspal.

This will be annoying, it will be a lot of work. But you can’t fix a problem if you don’t understand the cause first.

This exercise will quickly make you stop eating some high calorie foods you didn’t know you were eating.

Estimate How Many Calories You Burn

Calculate your basal metabolic rate (BMR) first. This is how many calories you would burn if you do nothing but rest in your bed for 24 hours (for muscle recovery, digestion, breathing, etc). This calculation depends on your gender, age, weight, and height.

Then multiple your BMR by your physical activity levels (PAL). This adds calories burned through daily activities. Most people have office jobs and walk less than 5000 steps a day. That gives a “sedentary’ multiplier of only 1.2.

Note that lifting weights doesn’t burn much calories. The sets only last a few seconds, and you spent most of your workout resting between sets. So lifting weights 3x/week does not make you any less sedentary. Walking +5k steps a day does.

Multiple your BMR x PAL to get your TDEE – your total daily energy expenditure. This the amount of calories you need to maintain your weight for your current age, body weight, and physical activity levels.

There are all kind of calculators you can find online to estimate your caloric intake. But usually the formula can be simplified for guys to your body -weight in lb x 10-12. Meaning a 90kg/200lb man usually needs about 2200kcal/day to maintain his body weight.

Create a Caloric Deficit to Lose Fat

To lose fat you decrease calories by about 500kcal/day to create a weekly deficit of 3500kcal (which equals about 1lb/0.5kg of fat per week).

Note that all this calorie calculation is just an estimation. It’s not going to be accurate. Because the original formula’s were developed using averages. Some people have higher metabolism than others. And it’s hard to know what your true activity level is.

So get a rough idea of how many calories you need to maintain your body-weight. Reduce about 500kcal/day from that. Then check how your body responds once you start. If you lose more than 1lb per week, you might be reducing calories too much. If you’re not losing 1lb/fat, you might be eating too much.

No online calorie calculator is 100% accurate. Many will give you too little or too many calories to eat, and confuse you. Only use calorie calculators to get an estimate. Adjust as you go.

Stop Wasting Your Time With Cardio

Cardio burns less calories than you think.

An hour on the treadmill burns about 500kcal max.

And that’s if you’re doing cardio at a moderately high intensity.

Most people in gyms aren’t burning that, they’re watching TV and reading magazines while dong the equivalent of a light jog/walk.

That’s not going to burn enough calories to make any significant calories to lose fat.

Think about it.

Let’s say you’re doing harder cardio for one hour. You’ll burn 500kcal max.

It only takes one Big Mac (without the fries/coke) to cancel out those 500kcal you spent an hour burning.

You’re not a Professional Athlete

Michael Phelps, the olympic swimming champion, can junk food all day while stay at 8% of body fat with visible abs.

But he’s swimming 4-6 hours a day. That’s easily 2-3000 calories per day burned.

We don’t have time to do cardio 4-6 hours. We have a job.

So we can’t eat whatever we want, and burn it later in the gym.

Because cardio and lifting weights doesn’t burn enough calories to get away with a bad diet.

That’s why most people need to eat less to lose fat.

Be More Active, But Don’t Count on That

It’s great if you can start to walk more, take your bicycle to work, etc.

That will all help to increase the amount of calories you burn.

But don’t count on that being enough to lose fat.

Walking burns very little calories. If you walk 5km/h (3 miles, at an average pace, on a flat surface), you’ll burn 250kcal max.

I really like to walk, and aim for 10,000 steps a day. But you’re not burning a ton of calories with walking unless you do a ton of it – which takes too much time.

Cycling burns more, easily 500kcal/hour. But again, how many hours can you do in a day?

Unless you can do hours of activity a day, you have to eat less calories than you burn to lose fat.

Lift Weights so You Don’t Get Skinny

A low body-fat is useless if you don’t have muscle to show for.

You probably want to lose fat to achieve a more attractive body. Less fat is more attractive than lots of fat. But a low-body fat without muscle is skinny. A skinny guy is less attractive than a muscular guy.

Therefore you want to build muscle by lifting heavy weights.

Most people who want to lose fat, do cardio. They hit the treadmill. But that’s boring (hence why that are of the gym is full of TVs and magazines). Cardio also doesn’t build muscle, it just burns fat. Most people hate cardio, and it’s hard to stick to something you hate.

Lifting weights is more fun. It builds muscle. It increases your metabolism, unlike the steady-state cardio most people do. Which mean you’ll burn more calories from lifting weights, and after your workout.

For best results, you must do free weight, compound exercises. That means Squats and Deadlifts. If you’ve never lifted weights before, just start with the empty bar to focus on form. Check my StrongLifts 5×5 program, it only takes three times week.

Frequently Asked Questions

How do I lose fat if I have a slow metabolism?

First, by eating less calories than your body burns. Second, by not using that slow metabolism crap as an excuse.

How do you know you have a slow metabolism? Did you measure that? How? Most peopel say they have a slow metabolism but they can’t back that up with anything. It’s just an automatic thing they say, and then use as an argument.

Yes, some people have a slower metabolism than others. But the program is the same for everyone: eat less calories than your body burns. Create a caloric deficit, and you’ll lose fat, whether you hve a slow metabolism or not.

What should I eat to lose fat?

This is is less important than the total amount of calories you eat. Again, the most important thing to lose fat is to create a caloric deficit. That implies that you can eat whatever you want, as long as you reach a caloric deficit.

However, you’ll get better results if you focus not just on the quantity of calories, but also quality. Eating more protein for example helps you lose fat by keeping you full longer and increasing the amount of calories you burn.

Meanwhile green vegetables like broccoli are high in fiber but almost zero in calories. Which means you can eat your stomach full of them while barely getting any calories in. This helps avoiding hungry while creating a caloric deficit.

So focus on eating lots of protein (meat, chicken, fish), vegetables (brocolli, spinach, salad) and then moderate amounts of carbs and fats.

Does eating fat makes you fat?

No, excess calories do.

You can and should eat health fats. But fat contains more calories per gram than carbs or protein (9g per calorie vs 4 for carbs and protein). In that sense, it’s easier to consume excess calories with fats.

But fats make you full faster, longer and slow down digestion. A bagel (carbs) with peanut butter (high fat) keeps you full longer than a plain bagel – even at equal calorie sizes.

So don’t avoid fats. Avoid eating excess calories.

How many meals should I eat to lose fat?

The answer to that is less important than the total amount of calories you ate. The number one thing to lose fat is to eat less calories than you burn.

There’s no real advantage to eat more frequent mails. Eating three meals per day like bodybuilders won’t increase your metabolism. That myth has been debunked a long time ago.

The main disadvantage to eating more meals when losing fat, is that some meals will be too small. They won’t keep you full.

For most people, three to four meals a day works best.

Do I have to do cardio to lose fat?

No. If you enjoy doing cardio, then fine do it. But you’ll build a better, more muscular body by lifting weights. It’s more fun as well.

If you want to burn extra calories, and hate cardio, try to walk more. Use your car less. Use Apple Health and aim for 10,000 steps a day.

How do I stop eating junk food?

Stop buying it. Don’t have it at home. Make it so you have to get out of your home to eat junk food. If you feel like it, you’ll probably be too lazy to get out of the home and buy it late at night.

You don’t have to stop eating your favorite foods by the way. I eat burgers and pizza once in a while. What you can do is to make your own version at home. Make your own burgers – without all the greesy cheese and sauces. You get the same taste but without all the calories.

How fast can I lose fat?

Faster than you can build muscle. One pound of fat is about 3500 calories. So you can easily lose one pound of fat per week if you eat 500kcal less per day. There’s no need to do crazy low calorie diets. They don’t work anyway as you’ll get hungry and then binge.

How much fat can I lose in one month?

You can easily lose 4lb in a month by eating 500kcal/day less. You will usually not lose pure fat when you lose weight. However the total weight loss will probably be higher when you first start dieting, as there will be some water loss. 10lb of weight loss within the first weeks is possible.

How much fat can I lose in one week?

1lb of fat is realistic. For this you need to eat 500kcal/day. That creates a caloric deficit of 3500kcal in a week, which is good for 1lb of fat.

Does diet or training matter most to lose fat?

Diet is more important. Because most people do not have the time to burn enough calories to lose fat through exercise. An hour on the treadmill only burns about 500 kcals. You can easily cancel that hour of execise by eating one big mac post-workout. That’s without the fries and coke that more people eat.

Different story for athletes. They’re notorious for having a bad diet. The Olympic Swimming Champion Michael Phelps for example. He had an estimated body-fat of 8% with visible abs. Yet he ate junk food all day.

The reason he gets away with eating lots of junk food is becuase he was swimming six times a week, for 4-6 hours a day. That’s easily 2000 to 3000 calories he burned.

We can’t train 4-6 hours a day because we’re not paid to do this. We have a job. That means we have to control our diet in order to lose fat.

What’s the difference between fat loss and weight loss?

Fat loss means reducing your body-fat percentage – the amount of fat you carry.

Weight loss means reducing your overall body-weight. This includes everything – fat mass, muscle mass, bones, organs, water weight, bowel content, etc.

Two people can be the same body-weight, the same height, the same age. But they can look completely different based on their fat level and muscle mass.

Just look at this picture:

BMI Comparison - Weight Loss vs Fat Loss

Both guys are 6 foot tall, 250lb, and 33.9 BMI.

But the guy on the left has less fat and more muscle mass.

Why does this matter? Because the average person who wants to lose weight, does it to look better.

Lowering your body-weight can be done by just dieting alone, without doing exercise.

But a low body-weight with little to no muscle mass is not going ot make you look better.

That is just going to make you look skinny.

So it’s not how much you weight that matters.

It’s how much muscle mass and fat you carry.

That’s why it’s better to focus on fat loss.

Should I weigh myself every day to lose fat?

You can. I do it. I use a digital scale, which connects to bluetooth to my phone. Everything is saved in Apple Health which creates weekly and monthly averages.

Just keep in mind that your body weight can fluctuate a lot on a day to day basis. I’ve experienced differences of up to 1.8kg (3.6lb) in 24 hours.

Factors that influence your weight include what’s in your stomach, bowels and bladder, and water loss/retention.

For example, eating salty food (like a big bag of potato chips) can easily make you gain 3lb the next day.

If you’re constipated or dehydrated, your body weight is also going to be higher.

Some people get demotivated when things like that happens, as they think they just got fatter from that meal the day before.

But you can’t gain 3lb of fat in a day. One pound of fat requires about 3500kcal. You’d have to eat 3x3500kcal = 10500kcal to gain 3lb.

There’s no way you ate 10500kcal the day before. So it’s just weight gain that will disappear the next days.

That’s why you should look at your weekly and monthly weight averages, not the daily fluctuations.

Try to weigh yourself under the same circumstances every day so the readings are more consistent.

I do it first thing in the morning after peeing and taking a dump, before I eat or drink anything.

Does BMI matter?

The Body Mass Index is helpful for average people to keep their weight in check. But not for weight lifters like us. Because it only takes height and weight into account, not muscle mass.

At my last health check I had a BMI of 26.38, which they categorized as overweight. Their recommendation was that I should lose 19kg (to end up weigh in only 60kg).

My waist is 85cm and I have visible abs. So obviously I’m not over weight. It’s just that I have more muscle mass than the average person doing BMI test.

BMI is useless for people who lift weights.

How many calories should I eat per day to lose fat?

The average sedentary guy weighing 90kg/200lb needs about 2300kcal/day to maintain his weight.

So a good starting point to lose weight would be to eat about 500kcal/day less. In this case, eating 1800kcal/day would create a weekly caloric deficit of 3500kcal. 1lb of fat is 3500kcal. So you’d lose about a pound of fat per week.

Do I have to count calories to lose fat?

It is possible to lose fat without calories. Many people do it. But the approach is the same: they are eating less calories. Either by reducing portion sizes, or by elimating certain foods (eating low carb is common, as carbs tends to be higher in calories).

The benefit of doing that is that it’s simpler. A lot of the time it’s not clear how many calories are in what you eat – like when eating out. And doing maths at every meal is no fun.

The drawback is that you’re doing guess work. If you don’t lose fat, or if you hit a plateau (which you will), you won’t know if it’s because you ate too much – you have no data to work with.

If you’ve never counted calories before, I definitely recommend you do to do it for at least a month or two three. You will learn how many calories there are in the foods you eat the majority of the time.

Once you’ve gone through that for a few months, you’ll be able to use that knowledge to instinctively eat some foods less than others, because you know those foods are higher in calories. This will help you form new eating habits.

That’s basically what I did. I counted calories for a while using good old spreadsheets. That made me realize that foods like pasta and rice where high calories, so I should watch with that. Now I haven’t counted calories and years, and watch out with carbs. That’s how I’ve been able to keep my weight stable and visible abs over the past 10 years or so.

Do I have to eat breakfast to lose fat?

No. The number one thing that matters to lose fat is to eat less calories than your body burns. As long as you create a caloric deficit, it doesn’t matter if you eat breakfast or not.

There’s fat loss advantage that eating breakfast will give you. Some people think that eating breakfast speeds up your metabolism, but that myth has been debunked over and over. There’s no difference between eating three vs six meals a days. Your total caloric intake matters most.

It’s true that people who eat breakfast are usually healthier – more likely to watch what they eat, exercise, and thus be leaner. Meanwhile, smokers and heavy drinkers tend to not eat breakfast in the morning. That may make breakfast eaters healthier, and leaner. But eating breakfast has nothing to do with it.

How can I track my fat loss progress?

The easiest way is using the US Navy equation.

  • Measure your waist, hip and neck circumference every week, at the same time.
  • Measure it three times, take the average, and note it down in a spreadsheet.
  • Use a self-measuring tape, it makes things a lot easier

You can measure your thighs, biceps and chest as well to track your muscle gains against your fat loss.

You should also take full body pictures once a month. Full body, head to toe, front, back and side. Wear the same clothes and lightning every time so you can easily compare progress. Taking more pictures isn’t necessary as your body doesn’t change that fast.

Since fat loss heavily depends on sticking to your diet and workout, you should track adherence too. You should aim to get 80% adherence to both. Meaning you’re within 200kcal of your daily calorie intake, and getting 10 workouts a month at least 80% of the time.

Remember perfection isn’t needed – it will make you fail. You will get results if you get things right 80% of the time. You can skip a workout once a month, and have some cake here and there, as long as you’re doing the right thing 80% of the time.

I’m skinny-fat. Should I lose fat or build muscle first?

If you’re more skinny than fat, focus on building muscle first. You do that by lifting heavy weights. Eat maintenance calories and focus on increasing your strength.

If you’re more fat than skinny, then focus on losing fat. Lift heavy weights to increase your muscle mass and avoid muscle loss from dieting. You should be able to build muscle and lose fat at the same time for a while.

What’s the best diet for fat loss?

The best diet is the one you stick to. Whatever diet you choose, if you can’t stick to it long-term, then the risk to regain the fat you lost is high.

Any diet will make you lose fat if it creates a caloric deficit. That part is easy. The hard part is how to keep the fat off in the long run. Many people regain the fat they lost because they chose a diet they can’t stick to long-term.

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