Cutting or shedding fat is simple on paper. You eat fewer calories than you burn, and your body makes up the difference from its stored energy. The catch is that fat isn't the only thing it can draw from. Muscle is on the table too, and that's the part you've worked hardest to build.

You can hold on to lean muscle while cutting by keeping your calorie deficit moderate, eating enough protein and continuing to lift heavy. BCAA amino acids (often shortened to BCAA aminos) and EAAs support that around training and between meals, but they work on top of your protein, not instead of it. At Nutritional Performance Labs (NPL), we break down how fast to lose weight, how much protein you need, what aminos do on a cut, when to take them and the signs your cut is costing you muscle.

Why Does a Calorie Deficit Put Muscle at Risk?

When you're in a calorie deficit, your body is short on energy and looks for it wherever it can. Most of it comes from fat, but some can come from breaking down muscle protein, especially if your protein intake is low or the deficit is too big.

Alongside protein, two things decide how much muscle you keep. The first is how fast you're losing weight. A review of evidence-based recommendations for natural bodybuilders suggests losing around 0.5 to 1% of your bodyweight a week to hold on to as much muscle as possible. For an 80kg person, that's 400 to 800g a week. The second is training. Lifting heavy tells your body the muscle is still needed, so keep your strength work and don't swap it for extra cardio.

Creatine helps here too, by keeping your training quality up when your energy is low. Find out how in Why Creatine Belongs in Your Fat Loss Stack.

How Much Protein Do You Need to Keep Muscle on a Cut?

Protein matters more than any supplement on a cut. It's the raw material your muscles are built from, and you need more of it when calories are low.

The International Society of Sports Nutrition (ISSN) recommends 1.4 to 2.0g of protein per kilogram of bodyweight a day for most people who train. During a cut, the bodybuilding review above recommends 2.3 to 3.1g per kilogram of lean body mass. Lean body mass is your weight minus your body fat. If you weigh 80kg at 20% body fat, your lean mass is 64kg, so you'd aim for roughly 150 to 200g of protein a day.

Spread that across three to five meals with 20 to 40g or more at each, rather than loading most of it into dinner. Whole food should do most of the work, with a protein shake to close the gap. If you're not sure which whey suits you, see our guide to the best whey protein in South Africa.

What Do BCAA Aminos and EAAs Do During a Cut?

Protein is made of amino acids. Nine of them are essential amino acids (EAAs), which means your body can't make them and has to get them from food or supplements. Three of those nine are branched-chain amino acids (BCAAs), called leucine, isoleucine and valine.

Leucine is the one that matters most for muscle. It acts as the switch that starts muscle protein synthesis, the process your body uses to repair and build muscle tissue. The ISSN recommends 700 to 3000mg of leucine per serving, alongside the other essential amino acids.

That last part is important. BCAAs flip the switch, but your body needs all nine EAAs to finish the job. If your protein intake is on target, BCAAs are a useful extra around training rather than a must-have. If protein is hard to hit on fewer calories, EAAs give you the complete set without the calories of a full meal.

When to Take BCAAs or EAAs on a Cut

• Training fasted or early in the morning. Take a serving before or during your session, so your muscles have amino acids available when you haven't eaten.
• During longer sessions. Sip a serving through the workout. In summer, mixing it into your water bottle also helps you drink more.
• Between meals and on rest days. When meals are spaced far apart on a lower-calorie plan, aminos give your muscles a top-up without adding many calories.

BCAA EAA 12:1:1 gives you BCAAs and the full set of EAAs in one shake. Each 15g serving has 5.4g of leucine at around 202kJ, so it fits easily into a deficit. Every NPL product lists each ingredient and its exact dose under our Full Label Transparency standard, so you can see exactly how much leucine you’re getting per serving.

If you prefer a straight BCAA, BCAA Amino Pro gives you 10g of BCAAs in a 2:1:1 ratio, with 5g of leucine and 5g of L-glutamine per serving.

For between meals or when you're away from the gym, Amino Gains comes in capsules, combining BCAAs with hydrolysed whey peptides, so there's nothing to mix.

Stick to the dose on the label, and don't count aminos towards your daily protein total.

Shop BCAA EAA 12:1:1.

Signs Your Cut Is Too Aggressive

A cut that's moving too fast usually shows up in the gym before it shows up on the scale.

• Your strength is dropping across most of your main lifts, not just on one bad day.
• You're losing more than 1% of your bodyweight a week, week after week.
• Your muscles look flat and you're tired all the time.
• Your sleep, mood or recovery are worse than usual.
• You're hungry constantly, even between meals.

If a few of these sound familiar, bring your calories up slightly and check your protein against the numbers above, but don't drop the heavy lifting.

Protect Your Lean Muscle This Summer

Keeping muscle on a cut comes down to three things. Lose weight at a steady pace, eat enough protein and keep lifting heavy. Our BCAA aminos and EAAs are designed to support exactly this stage of a cut, around training and between meals. Find yours in NPL's amino acid range in South Africa.

Frequently Asked Questions

Do BCAAs prevent muscle loss during a cut?

They can help, but they can't do it alone. BCAAs, especially leucine, switch on muscle protein synthesis, but your body needs enough total protein and all nine EAAs to keep muscle. Get your protein right first, then use BCAA aminos around training.

What's the difference between BCAAs and EAAs?

BCAAs are three amino acids, called leucine, isoleucine and valine. EAAs are all nine essential amino acids, including those three, so they give your body the complete set it needs to build muscle.

How much protein do I need to preserve muscle while cutting?

Aim for 2.3 to 3.1g per kilogram of lean body mass a day. For an 80kg person at 20% body fat, that's roughly 150 to 200g a day, spread over three to five meals.

How do I know if my cut is too aggressive?

Falling strength, losing more than 1% of your bodyweight a week and feeling flat and tired all the time are the clearest signs. Eat slightly more, check your protein and keep lifting heavy.

Can I take BCAAs on rest days?

Yes. Take them between meals, especially when your meals are spaced far apart. Your muscles are still repairing from training on rest days, so the amino acids are useful on those days too.