10 Best Low-Calorie Protein Powders, According to an R.D. (2024)

What Makes a Protein Powder Low Calorie?

The lowest calorie protein powders emphasize protein and minimize other ingredients like carbohydrates, fats, added sugars, artificial flavorings, and other additives that add additional calories to a protein powder. The lowest calorie whey protein is whey protein isolate—which involves additional processing that results in higher protein content and less carbs, fat, and lactose than whey protein concentrate.

However, it also depends on the actual amount of protein per serving. One gram of protein contains four calories. So, protein powders that have a higher protein concentration will naturally have more calories. More protein in a protein powder isn’t a bad thing, especially if your goal is to take in more protein. Most people shouldn’t turn away more protein for the sake of a few extra calories. But, it ultimately comes down to how much protein and how many calories you’re getting throughout the rest of the day.

What to Look For in a Low-Calorie Protein Powder

There are a few things Fernando considers must-haves when it comes to narrowing down a protein powder. All of the low-calorie protein powders on our list hit the standards below.

Third-party tested

Third-party testing means that the supplement has been evaluated by a lab that’s unaffiliated with the brand. A NSF, USP, Consumerlab, or Informed Choice (or Informed Sport or Informed Protein) certification offers unbiased verification that the supplement meets its label claims and is free from harmful contaminants, offering an additional layer of assurance for safety and effectiveness.

If a supplement isn’t third-party tested, Fernando recommends looking for other signs of integrity. Internal spot tests for heavy metals or other contaminants and transparency about ingredient sourcing are green flags. A CGMP stamp is also a plus—it signifies that a brand follows the current manufacturing practices outlined by the FDA; however, it isn’t superior to having an established third-party tester such as NSF, USP, Consumerlab, or Informed Choice.

Less than 150 calories

The normal range of calories for a protein powder is about 120 to 180 calories. “Aim for 150 calories or less from your protein shake if your goal is weight loss,” says Fernando. Keep in mind that if you mix your protein powder into milk or a smoothie, you need to account for those calories too.

20 to 40 grams of protein

The general consensus is to aim for roughly 20 to 40 grams of protein per meal over three to four meals throughout the day to build muscle (5). However, these numbers are an estimate. Your protein intake at a meal should come down to several factors including your weight, age, fitness goals, and how much protein you’re getting throughout the rest of the day, says Fernando.

One review suggests hitting a minimum of 1.6 g/kg of bodyweight, and a max of 2.2 g/kg of bodyweight to maximize the muscle-building benefits of protein (6). That comes out to 0.4 to 0.55g/kg of body weight in one sitting. For a 175-pound guy that’s about 32 to 44 grams of protein.

You might want to aim for the higher end of the range depending on your goals and age. For example, during weight loss studies suggest more protein can be helpful for maintaining lean muscle mass (5).Older adults also need to eat more protein at each meal to achieve the same level of muscle protein synthesis (7).

No added sugar

Protein supplements that contain added sugar might taste good, but they tend to have the highest calorie content per serving—so, you won’t find them on our list. Since theAmerican Heart Associationrecommends keeping added sugars to a minimum for overall health (7), choosing a protein powder with no added sugar is a win-win.

Unflavored protein powders are your best bet. Flavored protein powders that don’t contain added sugar often have artificial sweeteners. Some artificial sweeteners are better than others. Steer clear of aspartame and alcohol sugars like erythritol which have been linked to adverse health outcomes (8,9,10). Or at the very least keep these to a minimum. Stevia and monk fruit are safer, Fernando-approved options.

If you want flavor but prefer to avoid artificial sweeteners, aim to keep the total sugar under five grams per serving, says Fernando. The only exception is endurance athletes like runners or triathletes who might need the extra carbohydrates if otherwise failing to meet their needs.

Minimal additives

When it comes to protein powder, and any supplement for that matter, less is more. Look for a short ingredient list. Artificial ingredients, preservatives, and fillers add calories and are often ultra-processed, says Fernando. The only exception is plant-based protein powders, which may contain protein from multiple complementary sources to make a complete protein, increasing the protein quality of the product, and the number of ingredients on the nutrition label.

Protein Powder FAQs

You’ve got questions about protein powder, we’ve got answers.

Can protein powder have zero calories?

Nope. One gram of protein is four calories. By default, a protein powder that contains 20 grams of protein will contain at least 80 calories.

Can I drink protein powder for weight loss?

Yes. Since eating more protein while losing weight can help maintain lean muscle mass, protein powder can help you reach your goals. Still, aim to meet your protein needs through real, whole foods first. Whole foods contain other things—like vitamins and minerals which are important to overall health—that protein powder doesn’t.

Can protein powder replace a meal?

Ideally, it shouldn’t. “If you’re using protein powder as a snack, a 150-calorie protein shake will work, but it isn’t enough to replace a meal (which she notes should be at least 350 to 600 calories),” explains Fernando. You could replace a meal with a higher-calorie protein shake like ameal replacement shake, but she recommends sticking to balanced, whole foods when possible.