One of the most common weight-loss methods is to reduce your overall calorie intake. We're all pretty familiar with this approach; if your daily caloric needs are 2,200, for example, you might reduce your overall intake to 1,700 calories per day across the board (500 calories is the magic number, after all).
But a December 2019 study published in Advances in Nutrition reveals that this might not be the best way to go about it. The meta-analysis reviewed 18 studies and found that those who are actively cutting calories should actually eat more protein. Say what?!
The study found that for most adults, the current Recommended Daily Allowance of 0.8 grams of protein per kilogram of body weight gets the job done — it meets our everyday needs. But there are two specific instances when it's beneficial for us to eat more protein than is typically recommended: when we're strength-training to build muscle or when we're eating a reduced amount of calories — essentially, if you're in an anabolic (building) or catabolic (breakdown) stage.
For most of us, these findings challenge the way we typically think about weight loss and calorie restriction. We may know that all calories are not created equal, so we try to make healthy choices and get the most nutritional bang for our buck, but this reveals that if we're cutting calories to lose weight, we should be focused on getting enough protein and being more selective about where we're cutting those calories from. Some good places to start include reducing the amount of saturated fat, refined carbs, added sugar and high-sodium foods that we're eating. You'll find all three of these in ultra-processed foods.
Why Adding More Protein Is Beneficial for Weight Loss
When you cut calories and lose weight, some of the weight will inevitably be muscle rather than just fat. But maintaining your lean mass — or at least minimizing the amount you lose — promotes a higher resting energy expenditure (aka metabolism), which is crucial when you're trying to drop pounds and keep them off. After all, muscle burns more calories than fat.
Dietary protein is also beneficial for weight loss because it helps you feel full, requires more energy to metabolize and increases satiety hormones, as outlined in an April 2015 paper published in the American Journal of Clinical Nutrition.
So, How Much Protein Do We Need?
This study doesn't give us carte blanche to go and eat as much protein as we want, nor does it mean that eating more protein will necessarily lead to weight loss.
For most of us, if we're not engaged in some sort of regular resistance-training program or reducing our calorie intake, 0.8 grams of protein per kilogram of body weight per day meets our daily protein needs. So for a 150-pound women, this is about 55 grams of protein per day, and for a 185-pound man, about 67 grams per day.
But the truth is, as Americans, we're already overdoing it when it comes to consuming protein. As the December 2019 paper states, according to recent NHANES data, adults are eating 1.1 grams of protein per kilogram of bodyweight per day. And as the authors point out, if you don't fall into one of these anabolic or catabolic "stressed states," eating more protein doesn't prove to be beneficial.
If you are reducing calories or strength-training, eating closer to 1.3 grams of protein per kilogram of body weight is the optimal number to aim for, per the study.
According to this recommendation, if that same 150-pound woman has reduced her calories to lose weight, she might want to aim to eat closer to 88 grams of protein per day, and the 185-pound man should shoot for 109 grams.
But just like all calories are not created equal, all grams or types of protein are not created equal either. The quality of the protein you're eating will affect your overall health beyond weight loss.
The Best Sources of Protein
There are so many sources of protein available; the key is to look for what best fits your lifestyle (plant-based vs. animal proteins), sources low in saturated fat and foods that you enjoy eating. Here are some good options along with a few to eat sparingly:
Healthy Animal Proteins
- White turkey meat
- Chicken breast
- Low-fat cottage cheese
- Pork loin
- White fish
- Lean beef (look for 95 percent lean or greater)
Healthy Plant-Based Proteins
- Hemp seeds
Proteins to Limit
- Fatty cuts of red meat, including beef, pork and lamb
- Processed meats like sausage and bacon
- Poultry with skin
- Full-fat dairy products, including cream, butter and cheese
Bottom Line: If you're trying to lose weight and are taking the calorie-reduction approach, consider being a little more discerning when it comes to which foods you're trimming from your diet. Cutting refined grains, foods high in saturated fat and added sugars will prove to be beneficial, but keeping — and even upping — foods that are healthy sources of proteins may further your weight-loss success.
- Advances in Nutrition: "Protein Intake Greater than the RDA Differentially Influences Whole-Body Lean Mass Responses to Purposeful Catabolic and Anabolic Stressors: A Systematic Review and Meta-analysis"
- American Journal of Clinical Nutrition: "The Role of Protein in Weight Loss and Maintenance"
- Harvard Health Publishing: "How much protein do you need every day?"