Protein is the queen of every diet. If the body does not receive enough of it, health will inevitably suffer the blow. However, there are many different opinions about how much protein is really necessary.
Most official nutritional organizations recommend a fairly modest consumption. The baseline data points to 0.8 grams of protein per kilogram of body weight (1).
This in turn means:
-56 grams per day for the standard sedentary man
-46 grams per day for the standard sedentary woman
Although this amount may be enough to prevent protein deficiency, studies show that it is far from sufficient to ensure optimal health.
But the ideal amount of protein for each individual can depend on many factors, including activity level, age, muscle mass, physical goals and overall health.
So how much protein is optimal and how do lifestyle factors play a role?
What is protein and why is it useful?
Proteins are the main building blocks of the body. They are part of muscles, tendons, organs and skin.
In addition, they are used to manufacture enzymes, hormones, neurotransmitters and various small molecules with important functions. Thus, without proteins, life as we know it would not be possible.
Proteins are made of smaller molecules called amino acids, which are joined together like beads on a necklace. The bound amino acids form long protein chains, which then fold into complex shapes.
Some of those amino acids can be produced by the body, while others must be incorporated through the diet. The latter are called “essential amino acids”.
The consumption of protein should not only have quantity, but also quality. Generally, animal proteins provide all the essential amino acids in the right range so that the body can use them all. It is logical, considering that animal tissues are similar to ours.
So, if products such as meat, fish, eggsor dairy are consumed every day, surely the protein supply is correct. But in diets that don’t include animal foods, the challenge of getting the ideal dose of protein and amino acids is greater.
Most people won’t need protein supplements, but they can be helpful for athletes and bodybuilders.
Summarizing: Protein is a structural molecule made up of amino acids, many of which cannot be produced naturally by the body. Animal foods are generally high in protein and essential amino acids.
Protein can help you lose weight (and keep you not gaining it)
To lose weight, you need to consume fewer calories than you burn. And consuming protein can help that process by speeding up the metabolic process that eliminates calories and reducing appetite. This is fully supported by scientific studies (2).
Protein intake hovering around 25-30% of total calories accelerates metabolism to 80-100 calories per day, compared to lower-protein diets (3, 4).
But probably the most important contribution of protein to weight loss is its ability to reduce appetite and cause a spontaneous reduction in calorie consumption. Protein satisfies more than fats and carbohydrates(5).
In a study of obese men, protein intake of 25 percent of daily calories increased feelings of fullness, halved the desire to eat fast food at night, and also reduced obsessive thoughts about food by 60 percent (6).
In another study, women who raised their protein intake by 30 percent ended up consuming 441 fewer calories per day. In addition, they lost about 5 kilos in 12 weeks just by adding more protein to their diet (7).
But protein can not only help you lose weight, but directly not gain it from the beginning.
In one study, a modest increase in protein, from 15% of calories to 18%, reduced by 50% the amount of fat recovered by individuals who had already lost it (8).
A high protein intake also helps preserve muscle mass, which burns a steady small amount of calories.
Thus, consuming more protein will make it easier to maintain any diet that helps you lose weight, whether high or low in carbohydrates.
A protein intake that is around 30% of the amount of calories can be optimal for weight loss. This would be around 150 grams per day in someone consuming a diet of 2000 calories a day.
In short: a protein intake that is around 30% of total calories seems to be optimal for weight loss. It accelerates metabolism and causes a spontaneous reduction in calorie consumption.
More protein results in greater muscle mass and physical strength
As with most body tissues, muscles are dynamic and constantly break down and regenerate. And to gain muscle mass, the body must synthesize more muscle protein than it loses.
In other words, a net positive balance of protein, sometimes called a nitrogen balance, is needed because protein is high in this chemical.
For this reason, people who want a lot of muscle should consume a greater amount of protein (and follow a weight-bearing regimen, of course) (9).
In addition, people who want to maintain the muscle mass you’ve already generated will also need to increase their protein intake while losing body fat, because this will prevent the muscle loss that usually accompanies weight-loss diets (10).
When talking about muscle mass, studies generally do not take into account the percentage of calories, but the daily grams of protein per unit of body weight. A common recommendation for gaining muscle is 2.2 grams of protein per kilogram.
Numerous studies have tried to determine the ideal amount of protein to gain muscle mass and have reached different conclusions.
Some studies showed that more than 0.8 grams per pound of weight has no benefit (11) while others showed that consuming just over one gram of protein per pound of weight works well (12).
And while it’s hard to give exact numbers because the results in studies are conflicting, 0.7 to one gram per pound of weight seems like a reasonable estimate.
If you have a high level of body fat, then it is a good idea to use both lean mass or goal weight instead of total weight, because it is mostly lean mass that determines how much protein is needed.
Summarizing: It is important to consume protein if you want to gain or maintain muscle mass. Many studies suggest that a consumption of 1.5-2.2 grams per kilo is sufficient.
Other circumstances that may raise the need for protein
Beyond muscle mass and physical goals, active people need more protein than sedentary people.
If you own a physically demanding job or routine that includes walking, running, swimming, or any form of exercise, then you will need more protein. Endurance athletes also need it in good quantity, around 1.2-1.4 grams per kilo (13).
Older people also have higher protein needs, up to 50% higher (14). This helps prevent osteoporosis and sarcopenia (reduction of muscle mass), very significant problems in old age.
And those recovering from any type of injury also need more protein(15).
Summarizing: Protein requirements are elevated in physically active individuals, older people, and individuals recovering from injuries.
Do proteins have any negative effects on health?
It has often been said that a high-protein diet can cause kidney problems and osteoporosis. However, none of this is supported by scientific studies.
Although protein restriction helps people with pre-existing kidney problems, protein does not cause kidney damage in healthy people (16).
In fact, higher protein intake lowers blood pressure and helps fight diabetes, two of the highest kidney risk factors(17).
And if protein actually has any negative effect on kidney function (which has never been proven) this is outweighed by the positive effects on risk factors.
Proteins have also been blamed for causing osteoporosis, which is strange considering that studies show that it can in fact prevent it(18).
Overall, then, there is no evidence that reasonably high protein intake has adverse effects in healthy people.
Summarizing: Proteins have no negative effect on kidney function in healthy people and studies show that it improves bone health.
How to introduce protein into the diet
The biggest sources of protein are meat, fish, eggs and dairy. All of them contain the amino acids that the body needs.
But the truth is that it is not really necessary to track the amount of protein that is consumed. In a healthy person trying to remain healthy, only consuming quality protein at most meals (along with nutritious vegetables) should maintain the optimal range.
What does “grams of protein” really mean?
When we talk about “grams of protein,” we are talking about the nutrient, not grams of a food that contains it. A usual serving of red meat weighs 226 grams, but contains 61 grams of protein. One egg weighs 46 grams and contains 6 grams of protein.
What about the standard person?
If you are at a healthy weight, do not lift weights and do not exercise too much, 0.8 or 1.3 grams of protein per kilo of weight is a reasonable consumption. This means:
-59-91 grams per day for an average man
-46-75 grams per day for an average woman
But since there’s no evidence of harm and there is significant evidence of benefit, it’s better for most people to aim for higher protein intake than reduced ones.
(5) http://www.muyinteresante.es/salud/preguntas-respuestas/ipor-que-son-saciantes-las-dietas-ricas-en-proteinas(6) http://www.muyinteresante.es/salud/preguntas-respuestas/ipor-que-son-saciantes-las-dietas-ricas-en-proteinas
(10) http://ajcn.nutrition.org/content/early/2012/01/17/ajcn.111.026328(11) http://ajcn.nutrition.org/content/early/2012/01/17/ajcn.111.026328