Can You Lose Weight By Just Eating Protein?

  • Medical Reviewer: Dany Paul Baby, MD
Medically Reviewed on 10/11/2022
Protein does not cause weight loss. But a diet high in protein will keep you from feeling hungry for longer.
Protein does not cause weight loss. But a diet high in protein will keep you from feeling hungry for longer.

Overweight and obesity often lead to disorders like diabetes, heart disease, stroke, and hypertension (high blood pressure). Being overweight is bad for self-esteem, too. Losing weight needs a balanced approach — attention to diet and an exercise program that helps you burn calories. Protein is always an important component of your diet, but even more important when you're trying to lose weight. High protein diets are promoted for their efficacy in weight loss, and are they enough on their own?

What is protein?

You had protein to build muscle and other tissues. Enzymes, antibodies, and hemoglobin are proteins, too. Your body needs a regular supply of dietary protein for growth, repair, and metabolism.

Proteins are also used by the body to generate energy. One gram of protein can be metabolized to yield four calories. This is about the same as a gram of carbohydrate and half as much as a gram of fat. But the body generally saves proteins for more essential uses. 

Most protein in the diet is derived from meat, fish, eggs, milk, soy, lentils, and cereals. People following a vegetarian or vegan diet can also get adequate dietary protein to meet their requirements.

Does protein help in weight loss?

Weight loss depends on eating fewer calories than you use. This basic fact underlies the success (or failure) of all weight-loss diets and plans. Increasing your physical activity and reducing the calories in your diet leads to weight loss. Apart from this negative energy balance, your diet's content also matters. Food that promotes satiety and maintains metabolism despite reduced calories is the key to successful weight loss.

 A high protein diet (25% of total calories) and a typical protein diet (15% of total calories) will yield the same weight loss if both diets are similarly calorie-restricted. Protein does not cause weight loss. But a diet high in protein will keep you from feeling hungry for longer.

Meals that keep you full for a long time help you lose weight. Proteins are the most satisfying of the macronutrients in food. People who stick to high protein diets sustain weight loss and lean body mass. Diets providing between 1.2 grams and 2 grams of protein a day per kilogram control appetite, help in managing body weight, and reduce the risks for heart and metabolic disorders.

What is a high protein diet?

People with a sedentary lifestyle have a daily protein requirement of 0.8 grams per kilogram of body weight a day. There isn't a formal definition of high protein diets. Diets providing 1.2 grams to 2 grams of protein a day per kilogram are considered high protein diets. Weight loss diets usually recommend reducing carbohydrates and provide 25% to 35% of calories from protein.

High protein diets should aim to provide 25% of total calories from protein, 30% of total calories from fat, and 45% from carbohydrates. Extreme diets like the ketogenic diet reduce carbohydrate calories to less than 10% but are not sustainable for long.


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Should you try to lose weight by eating just protein?

Weight loss needs a negative energy balance. You must reduce your calorie intake to less than your expenditure to lose weight. Maintaining an intake of high protein with reduced calories is difficult with food items.

Food is rarely pure protein. Most food will also provide you with dietary fiber, carbohydrates, minerals, vitamins, and fats. These are all essential for you. Adopting a diet high in protein by using supplements could leave you deficient in vital nutrients. 

Protein adds a metabolic burden on your body, especially on the kidneys. A high protein intake for a long time can cause digestive, kidney, and bone disorders. People with a very active lifestyle can tolerate higher amounts of protein than those with a sedentary lifestyle.

Is a weight-loss diet enough for weight loss?

Weight-loss diets reduce your calorie intake to low levels. Women should have diets with 1200 to 1500 calories. Men should have diets with 1500 to 1800 calories. Your health care provider will consider your body weight and activity levels when planning your diet. Your aim should be to eat 30% fewer calories than your daily needs.

While diet control may help you lose weight, you need exercise to keep the weight from returning. You should aim for at least 150 minutes a week of physical activity, such as brisk walking. Higher activity levels are more successful at maintaining weight loss. 

Losing weight by dietary intervention alone is not recommended. You're likely to lose muscle mass as your body makes up the calorie deficit by using protein as well as stored carbohydrates and fat. A calorie-restricted diet combined with muscle-strengthening and aerobic activities keeps your bones, muscles, and heart strong as you pursue weight loss. Regular exercise will also reduce your risks of disorders like diabetes and high blood pressure.

Add a workout to your weight-loss plan

Adding protein to your food works to lose weight in the short term. To avoid gaining it again, add aerobic and muscle-strengthening activities to your weight-loss strategy. A balanced diet and exercise keep your bones, muscles, and heart strong and save you from health problems like diabetes and high blood pressure.

Medically Reviewed on 10/11/2022
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British Nutrition Foundation: 'Protein.'

Centers for Disease Control and Prevention: 'Health Effects of Overweight and Obesity,' 'Physical Activity for a Healthy Weight.'

Food and Function: Dietary protein intake and human health.'

International Journal of Environmental Research and Public Health: 'Ketogenic diet for obesity: friend or foe?'

Journal of the American Society of Nephrology: 'The Effects of High-Protein Diets on Kidney Health and Longevity.'

Nemours Children's Health: 'Is It Possible to Lose Weight Without Exercising?'

Nutrition & metabolism: 'A high-protein diet for reducing body fat: mechanisms and possible caveats.'

Nutrition Journal: 'Effect of a high protein diet and/or resistance exercise on the preservation of fat free mass during weight loss in overweight and obese older adults: a randomized controlled trial.'