The importance of protein intake is far underappreciated, especially as we age. Perhaps due to misleading interpretation of low-quality research (epidemiological studies, in particular), people have come to believe that high protein intake is harmful. Instead, there is abundant research demonstrating that high protein intake is extremely beneficial and safe.
Low protein diets are likely counterproductive to our health goals. In fact, in animal studies, to achieve the most weight gain, researchers have learned to do so by administering a low protein, high carbohydrate diet.
Absolute amount of protein matters most
When it comes to protein intake
, it’s important to consider the total amount of protein, the absolute amount, rather than protein as a percentage of energy intake. This is especially important because of the tendency to under-eat protein. If focusing on protein as a percentage of energy intake, any attempts to reduce food intake will result in decreased protein intake. Our bodies, however, don’t care about percentages, however; our bodies need an absolute amount of protein to support our lean body mass and for growth/repair, etc.
When pursuing weight loss, people tend to restrict calories, and in so doing, that percentage point becomes a very low amount of protein which is inadequate for optimal health. Thus, if one is losing weight and restricting protein intake, there will be loss of both fat and muscle, which is counterproductive and inevitably leads to weight regain.
Daily protein intake
Americans tend to consume most of their total daily protein at one meal, the dinner meal later in the day. Typically, protein intake at breakfast is the lowest of the day, with an average 12 g of protein. This amount of protein is not enough to stimulate protein synthesis and thus is effectively just contributing to calorie intake. Protein synthesis is essentially not happening until there is a sufficient spike in leucine intake, requiring about 2.5 grams of leucine, an amino acid that stimulates the mTor pathway. It appears that 30 g of animal protein is required to obtain 2.5 g of leucine, and twice as much plant protein is required to do the same.
Particularly problematic is when people follow the common advice from dietitians to eat smaller meals multiple times per day. They are not getting the recommended 30 grams of protein per meal and thus will not be sustaining their muscle mass appropriately. This dieting strategy, thus, leads to loss of muscle mass, which subsequently has negative effects on metabolism, functional status, and overall health.
Testing higher protein intake
A research group that is considered the world’s authority on protein set out to test the impact of increasing protein intake (ref). They compared the standard 12 g of protein at breakfast to a higher-protein breakfast containing 33 g, with the intent of hitting a leucine content of at least 2.5 g. In the experimental group with higher protein, there was 18% more fat loss, 30% less loss of lean body mass, improved fasting glucose, improved post-meal glucose response, and a 20% decrease in triglyceride levels.
How to optimize protein
There are three levels of recommendations that have come out of this and subsequent research.
- The first level is to aim for a total daily protein goal of approximately 110 to 140 g.
- The next priority is to aim for the minimum 30 g of protein per meal.
- Finally, to optimize our protein intake, we should target 3 factors:
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- Hit the above quantities of protein intake
- Consume high-quality protein
- Distribute protein intake across the day to stimulate protein synthesis multiple times
This strategy of protein intake appears to get the best results in terms of increased fat loss and improved maintenance of lean body mass (muscle).
