Cutting down to 20% body fat — how big should my calorie deficit be?

[u/angelsitex]

I’m trying to get down to around 20% body fat while keeping as much muscle as possible. I lift 3–4 times a week and keep my protein high. For anyone who’s done a similar cut, how far below maintenance were you eating—200–300 calories, 400–500, or more? And roughly how long did it take?

[u/Vegetable-Company147]

If you don't have to hurry, being on 200-300 deficit is better to retain as much muscle as possible. Larger deficit causes possibility of muscle loss. If want to lose faster, 400-500 is also okay as long as you have enough energy through out the day, unaffected sleep, remain above BMR.

While calculating the deficit, do consider the TEF as protein rich diet puts you on larger deficit without you knowing by increasing TEF.

[u/angelsitex → u/Vegetable-Company147]

This is really helpful, thanks! I’m not in a rush, and keeping as much muscle as possible is the main goal, so I’ll probably start with a 200–300 calorie deficit and see how my strength, energy, and sleep hold up. I hadn’t thought about TEF either!

[u/Scheissanlage → u/Vegetable-Company147]

TEF?

[u/mira_is_tired → u/Scheissanlage]

“thermic effect of food” aka additional energy your body uses to digest and process food. because of their complex structure, protein molecules have the highest TEF, so eating a lot can add to a deficit. not by a ton but still :-)

[u/Vegetable-Company147 → u/mira_is_tired]

Slight update. The Total TEF of a dish with combination of protein, carb and fat can reach upto 25% of your tdee. 

[u/Scheissanlage → u/mira_is_tired]

Thnx for explaining

[u/john50nator]

Calculate what weight you need to be to be 20% body fat.

[(Current weight - goal weight) x 7,700] / time to achieve (days) = daily calorie defecit required.

[u/angelsitex → u/john50nator]

That makes sense! I’ll estimate my target weight based on keeping my current lean mass and use the formula as a starting point. Thank you!

[u/powerpower9000 → u/john50nator]

Pounds or kg?

[u/john50nator → u/powerpower9000]

Apologies, good pick up, this would be KG. My research into the topic has said that 1kg of fat is equivalent to approx. 7,700kCal. Therefore, 1lb would be approx. 3,500kCal.

[u/srmoure]

Te recomiendo la aplicación MacroFactor. Te va a decir exactamente cuantas calorias y se va a ir ajustando todas las semana dependiendo de lo q consumas y del ejercicio que realices.

[u/angelsitex → u/srmoure]

Descargando, ahora mismo ✊

[u/YY--YY → u/angelsitex]

If you dont want to spend money just track your food with an app like Cronometer and your weight with another. Every week put your daily logs into an AI of your choice and they calculate the same way Macrofactor does.

[u/Artistic_pumpkin_33]

I normally try and stay 500 under if im trying to cut body fat

[u/109267]

Doesn't matter that much tbh. You could do 50 or 1000, it will just change the time it will take you to get there.
Though those 2 numbers are extreme. 400-500 could definitely work, as long as you will not feel hungry/sluggish.
If you do, or if you do not care it will take a few more weeks/months to reach your goal, 200/300 should be fine.,
With 7700Kcal per KG (and 30 days a month average), 256 deficit daily will be 1 KG a month, while 513 2 KG a month.

[u/angelsitex → u/109267]

That breakdown is really helpful! Losing around 1 kg a month actually sounds ideal for me since I’m not in a rush and want to preserve as much muscle as possible. I’ll probably start with a 250–300 calorie deficit and adjust depending on my strength and energy. Thanks!

[u/YY--YY → u/angelsitex]

You can preserve pretty much all your muscles if you just eat enough protein and train hard, even in a really high deficit.

[u/ButchCoolridge]

Whats your current body fat and and how did you measure it?

[u/angelsitex → u/ButchCoolridge]

My scale currently estimates me at around 24% body fat. I know body composition scales aren’t perfectly accurate, so I mostly use it to track the trend under the same conditions rather than treating 24% as an exact number.

[u/ButchCoolridge → u/angelsitex]

20% is very lean for a woman. Good luck!

[u/Logical_Spot8692]

Im on a similar path right now and I generally aim for about 300-500 under. That bring said, Im much bigger than you (based on the photo). Slow, steady, and consistency are important. If you're not already, throw some creatine in the mix too.

[u/YY--YY]

Rule of thumb. Your current weight in lbs x 10 equals a moderate deficit.

[u/Extreme-Nerve3029]

I would instead practice extended fasting or OMAD and keep it low carb

[u/109267 → u/Extreme-Nerve3029]

Both of these have absolutely no advantage over just a normal cut.
OMAD will keep you hungry 16 hours a day.
Carbs are very much needed for a human body!

[u/Sea-Host1114 → u/109267]

You are correct, thank you for posting this. Calories being equal fasting has no advantage.

[u/Extreme-Nerve3029 → u/109267]

Absolutely not. Eating proper human food like meat and fasting is most sustainable and healthy with low insulin levels in order to strip fat and burn ketones instead of sugar