Can eating more protein improve your mood? A nutritionist explains

As a personal trainer, I’m always telling clients they need enough protein to help build and maintain muscle mass, fuel workouts, and boost recovery and repair. But could protein improve mood, too? Until now, it hadn’t been at the forefront of my mind.

Kerry Beeson BSc (Nutr, Med), a nutritional therapist at Prep Kitchen, says protein consumption could support mental health. “It's well-established that our diet can have either a positive or negative effect on our overall well-being,” she explains.

“Certainly, B vitamins like biotin and folate are known for their ability to help support the nervous system and good psychological function, whereas a high sugar diet is increasingly associated with poorer mood or wellbeing. Protein might not be the first thing you think of when you want to change your diet to support good mental health, but emerging research suggests that protein consumption could also affect mood.”

Here’s everything you need to know.

What is protein?

Protein is one of the three key macronutrients alongside fat and carbohydrates, and each has a purpose for keeping the body functioning as it should. Protein is made up of amino acids, which are like little building blocks for muscle repair and growth; fat is your body’s second-best fuel source, helping the body absorb vitamins and promoting cell function and insulation; carbs are your body’s main fuel source, breaking down into glucose and storing as energy ready to be used by your cells and muscles.

Your body breaks protein down into amino acids, which act as a currency for building muscle. As such, you’ll need to fuel your body with enough protein to support the turnover process. But protein isn’t just about muscle repair and growth; it contributes to hormone regulation, neurotransmitter function, and tissue repair, too.

If you’re wondering how much protein you need to build muscle, we can’t stamp a number on everyone, as your needs will depend on goals, how often you exercise (and what you do), general activity levels, age, and sex.

As a guide, I spoke to Professor Stuart Phillips, a muscle health and protein expert, who recommends between 1.6 and 1.8 grams of protein per kilogram of body weight “for most people" daily.

Two ways protein may improve mood

According to some researchers and nutritionists, protein plays a role in well-being. Here’s how.

Neurotransmitter synthesis

According to Beeson, protein is required for neurotransmitter production, which provides the body with little chemical messengers that “send instructions between our nerves, muscles, or glands.” In particular, serotonin and dopamine are active in the brain, helping regulate sleep, emotion, appetite, and cognitive function.

“Research is still evolving, but it's suggested that low protein intake may contribute to poor availability of the precursors needed for neurotransmitter synthesis,” Beeson explains.

“Dopamine and serotonin are derived from the essential amino acids phenylalanine and tryptophan. The body can't synthesize these amino acids, so we need to source them from our diet. They are found in high-protein food sources like eggs, soybeans, fish, beef, and chicken.” Tryptophan, for example, is a precursor to serotonin, which is closely tied to mood and stress responses.

It’s also important to consider your gut. The vagus nerve is responsible for your gut-brain connection. Did you know, according to research, roughly 90% of serotonin is produced in the gut? Therefore, adequate protein intake could indirectly support emotional regulation via your gut health.

However, from the research available, it's hard to measure a clear and defined link between improved mood as a direct result of increased protein intake in a trial, and more, it's the knock-on effect of protein on the body and mood over time.

Blood sugar balance

Beeson suggests that fluctuating blood sugar levels might affect mood in some people: “When blood sugar levels are high, it can make us feel tired and sluggish, and low blood sugar can make us feel anxious and irritable.

"These fluctuations are typically caused by eating sugars and refined carbohydrates, which are quickly digested and released into the bloodstream. This causes an initial spike in blood sugar, followed by a slump in energy and mood for some people.”

Protein takes longer to digest than carbs and helps slow carb digestion, helping stabilize blood sugar levels. This may help some people avoid the negative effects associated with poor glucose metabolism.

But it shouldn't replace your existing medication if you have diabetes or related conditions that need close monitoring.

However, Beeson is quick to look at sources of protein and their impacts. “Animal-based protein sources are typically higher in protein and are ‘complete' proteins, meaning that they contain all of the nine essential amino acids,” she says. “To ensure a broad range of amino acids and other valuable nutrients, it's best to eat a broad range of protein foods from both animal and plant sources.”

She adds that vegetarians or vegans should combine different types of plant sources each day, such as nut butters with wholegrains, to boost the likelihood of meeting amino acid requirements.

Bottom line

Protein may help improve mood in some people by supplying amino acids to make neurotransmitters, some of which regulate processes like appetite, mood, and sleep. This crucial macro also keeps you sated and slows carb digestion, helping to manage blood sugar spikes.

While increasing protein intake could contribute to a better mood, it shouldn’t be seen as a fix-all, and should be approached carefully. Your recommended daily intake is individual and depends on goals, weight, sex, activity level,s and more. You might already be consuming enough protein, so it’s important to look at your metrics before jumping up your numbers.

I recommend learning how to calculate your macros to help you get started. You can consume too much protein, so remember that balance is key.

Also, remember that low mood (at times) can be normal, and context matters. Your mood can be influenced by sleep, stress, exercise, and existing health or genetic conditions. If you suspect a wider health condition, always consult your physician or a qualified medical professional and seek the proper guidance and support you need.

A balanced diet, exercise, and monitoring other lifestyle factors like sleep hygiene and sources of stress should also be considered to support emotional well-being.

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