There’s much confusion around how much protein you should consume when trying to lose fat. Old school bodybuilders believe they should eat protein every few hours, whereas others fear the potential negative health effects of high-protein dieting.

In this article, we will talk all about the evidence regarding protein for fat loss. Does eating more protein actually help when you are in a caloric deficit? And are there any health concerns when it comes to high-protein dieting? Sit back and put your reading glasses on to learn more!

About Protein

Before we delve into the science behind protein and fat loss, let’s get a clear idea of what protein actually is. We know it helps with building muscle, but there is more to protein than many people think.

Protein is a structural nutrient, meaning that protein is mainly used for building up bodily tissues. As examples, your hair, skin, and eyes all contain protein. But the tissue in which protein probably has the most prominent role is in muscle.

Your muscles are made of the molecule, protein. In this case, also known as “muscle proteins.” These proteins are made up of something that probably sounds familiar: amino acids. Protein is made up of 21 amino acids, of which 9 are essential.

The reason the 9 amino acids you see left above are “essential” is that your body cannot synthesize these amino acids on its own. You need to obtain essential amino acids from your everyday protein sources like beef, fish, and lentils.

This immediately explains why protein is an essential macronutrient for survival. Protein provides the amino acids that your body can’t produce for important physiological processes like muscle function and health maintenance of other tissues.

How Protein Affects Fat Loss

Now that we better understand what protein does, we can dive a bit deeper into protein and fat loss.  In the scientific literature, we consistently see that those who maintain a high-protein diet tend to lose more fat and maintain more muscle. A 2017 review paper points out that this is because of three specific effects of protein:

  • Enhanced satiety
  • Higher energy cost of digestion
  • Promotes muscle retention

Let’s take a closer look at each of these effects.

Protein & Satiety

Protein is commonly known as the most satiating macronutrient. Multiple research reviews show protein is more filling than carbohydrates and fats. So increasing protein intake tends to aid fat loss by making you feel more satisfied while staying in a caloric deficit.

A classic example of this is a 2005 study by the University of Washington. When the participants increased their protein intake from 15 to 30% of daily caloric intake, they perceived a sustained decrease in hunger and their spontaneous food intake dropped. This eventually helped them lose more fat.

Higher Thermic Effect

When you eat a 400 calorie-meal, not all 400 calories are directly used to fuel your activities. A small portion of the energy you’ve consumed is directly used for the digestion of nutrients. This is known as the thermic effect of food.”

protein for fat loss

The macronutrients protein, carbs, and fat all have a different thermic effect per 100 calories consumed.

  • Protein: 20-30 calories
  • Carbs: 5-10 calories
  • Fats: 0-3 calories

You require more energy to digest protein since it is a complex nutrient. Because of this, eating more protein slightly enhances your daily energy expenditure. This is also part of the reason why it’s hard to gain fat on a high-protein diet.

Muscle Preservation

Having a successful fat loss phase doesn’t just involve weight loss. What most people are looking to do is lose fat while at least maintaining the muscle they currently have. Protein plays an important role here since it affects the composition of the weight you lose when in a deficit.

Having a high-protein diet has repeatedly been shown to increase muscle retention while in a caloric deficit. This makes sense. Muscle protein breakdown increases when you are in a deficit, so your body likely is also in need of more protein.

A good example of this is a 2010 study. In this study, a protein intake of 2.3g/kg (of total body weight) resulted in significantly more muscle preservation than a protein intake of 1g/kg in resistance-trained men.

All in all, current evidence supports that if you have a low-to-moderate protein intake, it’s beneficial to consume more protein for fat loss and muscle preservation.

How Much Protein Do You Need?

The RDA (recommended daily allowance) of protein in the United States currently is a daily protein intake of 0.8g/kg body weight (0.36g/lb). This recommendation applies to the “average Joe”, who doesn’t lift weights and is mostly sedentary. But for those that train consistently and are looking to maximize their gains, higher protein intakes are needed.

A 2017 meta-analysis compiled the data from 49 studies on protein intake and muscle growth to provide evidence-based protein intake recommendations. The researchers found that a good protein range for muscle growth is around .1.6g-2.2g/kg of body weight (0.7g/lb).

For an 80kg male, this is around 130-175g of protein per day. If you are obese or overweight, use your lean body mass instead of total body weight to calculate the right protein amounts for you.

A protein intake of 1.6-2.2g/kg is also a good range for feeling more satisfied. But I want to emphasize that there’s nothing wrong with starting at 1.2-1.5g/kg if you are not used to high-protein dieting yet. Research shows that an increase in protein intake as small as 5% helps with losing fat. So if a protein intake of 1.6-2.2g/kg sounds intimidating, have a small increase instead that’s realistic for you and gradually build up your protein intake.

Is A High-Protein Diet Safe?

Now that you know why protein is beneficial for fat loss and how much you need to achieve the benefits, we’re going to look into the health effects of a high-protein diet.

Because low-protein diets are used for treating some existing health conditions, like kidney disease, many think a high-protein diet is also harmful to healthy individuals. But the evidence against this assumption has been increasing in the past decade.

Protein for fat loss

Several review papers show no long-term negative effect of high-protein diets on renal function or overall health. In a 2016 study, researchers made bodybuilders maintain a very high-protein intake of 2.5-3.3g/kg of total BW for 12 months. There was no negative effect in any health marker. This is in line with recent experimental research.

So for overall healthy individuals, there’s no need to fear a high-protein intake. If you stay reasonable with your protein consumption and have an overall nutritious diet, protein won’t do harm.

Practical Takeaways + Fat Loss Checklist

  1. Protein is a structural nutrient. Protein involved in maintaining proper muscle function and the health of other bodily tissues.
  2. A high-protein diet is generally favorable for fat loss because protein is very satiating, has a high energy cost of digestion, and promotes muscle retention.
  3. A protein intake of 1.6-2.2g/kg of body weight is effective for most people. If you are not used to high-protein dieting, first make a small increase in your protein intake. From there on gradually build up your protein intake.
  4. High-protein diets are safe for overall healthy individuals. A multitude of research reviews shows no negative health effect after years of high-protein dieting.

I hope you’ve enjoyed reading this article and can apply a few of the discussed concepts in your nutrition. If you want more detailed information on how to set-up a complete fat loss phase, check out my fat loss checklist. It goes into detail on how to approach a fat loss phase effectively. Subscribe to my mailing list by leaving your email below and I’ll send it to you!