Why Protein Is So Good for Weight Loss

No magic wand guarantees weight loss because our bodies are all so different. But your food choices, especially the balance of macronutrients (fat, protein, and carbohydrates), can make a significant impact.

protein rich foods including fish, eggs, meat, and nuts
Caitlin Beale, MS, RDN
— Signos
Health & Nutrition Writer
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Science-based and reviewed

September 21, 2023
May 26, 2022
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Of all the macronutrients, protein comes in first for weight loss. It keeps you satisfied and helps with cravings because it stabilizes blood sugar levels. It also helps preserve muscle mass as you're losing weight.

Let's take a deep dive into why protein helps with weight loss and how you can easily incorporate more protein-rich foods into your diet.

<p><strong></strong><p class="pro-tip"><strong>Learn about </strong><a href="/blog/protein-before-after-workout">protein before & after exercise</a></p></p>

What Protein Is, and Why We Need It

Protein is an essential macronutrient that plays many roles in the body. Most notably, it is responsible for the growth and repair of tissues. Every cell in the body contains protein, and it is used to build and maintain muscle, skin, hair, and nails. 

Additionally, protein is essential for making enzymes and hormones, and it helps to transport nutrients and oxygen throughout the body. Without protein, our bodies would simply not be able to function properly, which is why the body will break down its own muscle to use for essential functions if the diet isn't providing enough.

Protein is made up of smaller units called amino acids. There are 20 amino acids that the body needs to function, and 9 of these are considered essential because the body cannot produce them on its own. This means that we must get them from the foods we eat.

How Protein Helps With Weight Loss

Several studies show that protein helps people with weight loss even without changing anything else in their diet (like cutting calories). It supports lean muscle mass while reducing body fat, and it helps people feel fuller for longer so that they are less likely to snack. One study found that eating a high protein diet (thirty-five percent total calories) divided into six meals a day decreased body fat and abdominal body fat. 

Protein may also help with weight loss maintenance. Higher protein diets may be easier to maintain than other changes in macronutrients (like very low-carb diets) and therefore help people continue to eat well and maintain weight loss.

But what is it about protein that makes it so effective for weight loss? Let's take a look at some of the reasons why.

<p><strong></strong><p class="pro-tip"><strong>Learn about </strong><a href="/blog/sustainable-weight-loss">the benefits of sustainable weight loss</a></p></p>

Protein Keeps You Satisfied Between Meals

One of the main reasons protein is so effective for weight loss is that it helps keep you satisfied between meals. Severely cutting calories fail to produce long-term results for several reasons, but one is simply because people feel too hungry to sustain them. On the other hand, protein takes longer to digest than other nutrients, minimizing blood sugar spikes which helps you feel full.

Some research also suggests a protein-specific appetite exists where people will seek out more food if the amount of protein in their diet is limited, but if protein needs are met, they will naturally eat less. 

This theory was examined in a study where people were given different percentages of protein on different days but could eat as much as they wanted. When protein percentages dropped from 15 to 10 percent, people ate more calories. But when the total percentage of protein increased from 15 to 25 percent, calorie intake remained the same. In other words, as people ate more protein, they naturally ate less of the other macronutrients.

A study examining healthy women reported less hunger after eating a protein-rich yogurt snack. They also stayed satisfied longer and ate slightly less at dinner than people who snacked on foods with more carbs or fat. 

woman standing in a kitchen eating a bowl of berries and yogurt
Eating high-protein meals like greek yogurt with berries has been shown to curb appetite.

Another study found that when protein was increased from 15 to 30 percent of total calories (but carbohydrates remained the same), people naturally decreased their total calorie intake and lost weight and fat mass.

The other reason protein may keep you full is because of the impact on hunger hormones. Hunger hormones, such as ghrelin, tell your body when it's time to eat. Studies show that protein can help regulate these hormones and keep hunger at bay.

<p><strong></strong><p class="pro-tip"><strong>Learn about </strong><a href="/blog/lose-weight-women">the science behind weight loss for women</a></p></p>

Protein Preserves Lean Body Mass as You Lose Weight

As mentioned earlier, protein is essential for maintaining muscle mass. If you cut calories and drop weight, you could lose muscle mass instead of fat. This is one reason calorie-restricted diets aren't always the best idea. 

Protein helps preserve lean body mass as you lose weight, even when calories are restricted. Several studies found that individuals who increased their protein intake lost more fat mass and less muscle mass than those who didn't increase protein.

Lean muscle is also metabolically active compared to fat tissue, so you can positively impact your metabolism by preserving muscle.

It Takes More Energy to Break Down Protein 

Another reason protein helps with weight loss is because it takes more energy to metabolize protein than other nutrients (known as the thermic effect) to burn more calories. It's likely only a small boost, but it could contribute to the overall benefits of eating protein for a healthy weight.

One study showed that individuals who ate a high-protein diet had a higher energy expenditure than those who ate a low-protein diet. Another small study found that eating a high-protein meal led to a twofold higher energy burn than a high-carb meal.

<p><strong></strong><p class="pro-tip"><strong>Learn about </strong><a href="/blog/low-carb-diets-weight-loss">low-carb diets for weight loss</a></p></p>

Protein Keeps Blood Sugar Balanced

While protein has a minimal effect on lowering blood sugar it can help keep blood sugar levels balanced by slowing the absorption of carbohydrates into the bloodstream. This is beneficial because it can help minimize blood sugar and insulin spikes that play a role in fat storage.

Studies show the benefits of high protein diets for weight loss and blood sugar balance for people with type 2 diabetes, but anyone can see the benefits.

<p><strong></strong><p class="pro-tip"><strong>Learn about </strong><a href="/blog/mitigate-high-glucose-spikes">controlling blood sugar spikes</a></p></p>


How Much Protein Should You Eat for Weight Loss?

Each person will require different amounts of protein depending on factors like age, weight, activity level, or medical conditions. The Recommended Daily Allowance (RDA) for sedentary adults to prevent deficiency is 0.8 grams per kilogram (kg) of body weight. Usually, this is between 15 and 20 percent of total calories.

However, some research suggests that the ideal protein range for healthy adults is closer to 1.2 to 1.5 grams per kilogram.  This is especially true if you are active or trying to build muscle. 

To see what works best for your body, you can also experiment with the different macronutrient percentages—like increasing your protein and dropping your carbohydrates.

<p><strong></strong><p class="pro-tip"><strong>Learn about </strong><a href="/blog/cgm-data-weight-loss">using CGMs data for weight loss</a></p></p>

woman lifting weights at the gym
Getting enough protein is crucial if you want to build or maintain lean muscle.

Good Sources of Protein for Weight Loss 

  • Chicken
  • Turkey
  • Wild salmon
  • Grass-fed beef
  • Cod
  • Tuna
  • Shrimp
  • Quinoa
  • Tofu
  • Lentils
  • Edamame
  • Black beans
  • Greek yogurt
  • Cottage cheese
  • Eggs
  • Almonds
  • Walnuts
  • Pistachios 

People often think of protein as something that comes from animal sources. Animal protein like chicken, turkey, and fish are excellent protein sources, but there are plenty of plant-based sources of protein that can be just as beneficial for weight loss. One study compared two diets that either emphasized plant or animal-based protein sources, and both led to comparable amounts of weight loss.

Quinoa, tofu, lentils, legumes, and edamame are excellent protein sources. The trick is to learn how your body responds because although they are high in fiber and protein, they can spike blood sugar for some people

Greek yogurt, cottage cheese, and eggs are also high in protein. One study found that eating eggs for breakfast increased satiety (feelings of fullness) significantly more than eating a bagel for breakfast.

In addition to containing protein, nuts and seeds are a great source of healthy fats and fiber. Almonds, walnuts, and pistachios are all delicious choices for snacks or toppings on meals.

<p><strong></strong><p class="pro-tip"><strong>Learn about </strong><a href="/blog/nuts-blood-sugar">the best nuts to stabilize blood sugar</a></p></p>

Are Protein Powders Good for Weight Loss?

Protein powders used to be just a supplement for bodybuilders and people trying to gain muscle mass. However, protein powders have become increasingly popular as a quick and easy way to get additional protein into your diet.

Whey protein is the most popular type of protein powder. It's a complete protein which means it contains all the essential amino acids your body needs. It's easily absorbed and has a lot of beneficial research behind its use for satiety, weight loss, and lean muscle.

One study found that daily whey intake led to weight loss without any other dietary changes. Several studies also point to whey protein and satiety, which can lower overeating or food cravings.  This may be related to the positive effect on hunger hormones that help to suppress appetite.

But whey isn't the only protein supplement option. Some people can't tolerate dairy or prefer plant-based protein powders. Other types of plant-based protein powders include:

  • Pea protein
  • Hemp protein
  • Pumpkin seed protein

While soy-based foods like tofu are good protein choices, soy protein powders are heavily processed, so other options may be a better choice. Brown rice protein is another plant-based protein often recommended, but rice can contain high amounts of arsenic from the soil it is grown in, so you may want to avoid these too.

<p><strong></strong><p class="pro-tip"><strong>Learn about </strong><a href="/blog/dairy-blood-sugar">what happens in your body when you eat dairy</a></p></p>

woman blending a smoothie with whey protein, berries, and greens
Adding whey powder to a smoothie is an easy way to boost your protein intake.

Easy Ways to Add More Protein to Your Diet

  • Add protein powder to shakes and smoothies. This is an easy way to get in an extra serving or two of protein per day. Make sure your protein includes fiber and healthy fat to avoid blood sugar spikes.
  • Snack on high-protein foods like nuts, seeds, hard-boiled eggs, or yogurt. 
  • Eat more protein at breakfast. Eggs, oatmeal with protein powder, and Greek yogurt are great options. Try making protein pancakes for breakfast by mixing together some eggs, oats, and protein powder is a great way to start your day with a healthy dose of protein.
  • Use high-protein condiments like hummus, tahini, or peanut butter. 

Using a CGM to See How Protein Affects Your Blood Sugar

Using a continuous glucose monitor (CGM) lets you see exactly how a high protein diet impacts your glucose levels. When you wear a CGM, it will show how your blood sugar rises and falls throughout the day in response to what you eat. With this info, you can monitor trends and track your appetite or weight to see what works best for you.

<p><strong></strong><p class="pro-tip"><strong>Learn about </strong><a href="/blog/what-is-a-continuous-glucose-monitor">how CGMs work</a></p></p>

The Bottom Line: Protein Supports a Healthy Weight

Protein is an essential nutrient that plays a role in weight loss, muscle growth, satiety, and more. If you're looking to increase your protein intake, there are a few easy ways to do so. Adding protein powder to shakes and smoothies, snacking on high-protein foods, and eating more protein at breakfast are great ways to increase your daily protein intake. 

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Topics discussed in this article:


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About the author

Caitlin Beale is a registered dietitian and nutrition writer with a master’s degree in nutrition. She has a background in acute care, integrative wellness, and clinical nutrition.

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