Can a Low Protein Diet Help Lose Weight?

 

A high protein diet has long been recognized for its weight loss and health benefits. However, misinformation is spreading on social media platforms that a low protein diet is preferred.

Kelsey Costa, registered dietitian and science communications officer at Examine.com, said any potential benefit of long-term protein restriction is likely offset by an increased risk of sarcopenia, an age-related and progressive loss of muscle and strength.

Dietitian and author of “How Not to Eat Ultra-Processed”, Nichola Ludlam-Raine, also said the claim that low protein diets may be better for weight loss is nuanced.

“High protein diets are known to promote satiety, preserve muscle mass during weight loss, and increase thermogenesis,” Ludlam-Raine explains.

“On the other hand, lower protein diets could potentially lead to weight loss due to reduced calorie intake if protein-rich, calorie-dense foods are replaced with fruits, vegetables and whole grains.”

Crucially, though, Ludlam-Raine said that a low protein diet might not be sustainable for everyone as protein is critical for maintaining muscle mass and overall metabolic health.

Similarly, Costa explained how low protein intake may make weight loss difficult in the long term.

“A very low protein diet may initially result in weight loss, likely due to resulting calorie restriction overall, like any other highly restrictive diet,” she said. “But without adequate protein intake, this calorie restriction can result in the loss of both body fat and muscle mass.”

“The loss in muscle mass may ultimately decrease metabolism and lead to further weight regain when the diet is stopped,” she added.

Ludlam-Raine said that reduced intake of some proteins, such as red meat, may be linked to increased life span. But this is likely due to the heart health benefits rather than the reduction in protein.

Another potential benefit may be disease prevention, especially for some people with pre-existing conditions.

“Lower protein intake has been associated with reduced risks of certain diseases, such as kidney disease (in those with uncontrolled diabetes) and some cancers in certain people – particularly those who may eat a lot of processed red meat,” Ludlam-Raine explains.

“However, these benefits largely depend on the quality and source of the proteins, as well as the overall diet composition,” she points out.

There are also notable risks with eating a low protein diet.

“Inadequate protein can lead to muscle atrophy, particularly in older adults,” says Ludlam-Raine.

It can also cause nutrient deficiencies. “Proteins are essential for providing certain vitamins and minerals, and a low protein diet may result in deficiencies in nutrients like B12, iron, and zinc,” she explains.

Additionally, a weakened immune function may be another by-product of low protein intake.

“Proteins are crucial for the immune system, and insufficient intake can impair the immune response,” Ludlam-Raine explains.

“The recommended daily intake of protein varies by age, sex, and activity level,” says Ludlam-Raine.

“It’s important to remember that protein is essential for life, with a minimal requirement of at least 0.8g of protein per Kg of body weight a day,” she notes.

 “Generally, 0.8 grams of protein per kilogram of body weight is sufficient for most adults, while athletes and older adults may require more, around 1.0 to 2.0 grams per kilogram.”

The kind of protein you eat matters, too. Protein sources can be divided into animal proteins (like meat, poultry, fish, eggs and dairy) and plant Proteins (such as beans, lentils, tofu, tempeh, nuts, seeds and whole grains).

Animal proteins are complete proteins containing all the essential amino acids that we need. They are beneficial for muscle mass maintenance and overall health due to essential nutrients such as vitamin B12 and calcium as well as iodine, but should be consumed in moderation in comparison to plant-proteins,” says Ludlam-Raine.

While some plant proteins may be incomplete, they can be “combined to provide all essential amino acids  and they are generally lower in saturated fat and therefore can be beneficial for heart health and weight management.

A mix of plant-based and animal-based protein sources is best for a healthy diet.

“It’s a good idea to mix plant and animal protein sources to ensure a variety of amino acids and other nutrients,” Ludlam-Raine adds.