If you’re watching what you eat, you already know that all fats are not the same. There’s the ‘good’ poly- and monounsaturated versus the ‘bad’ saturated and trans fats. The same is true of carbohydrates, where you have slow-burning carbs from whole grains versus the rapidly digesting simple sugars that can create energy spikes and crashes. A study published in the journal Nutritional Neuroscience suggests varying your protein intake can be beneficial to mood and brain chemistry.

Brain neurotransmitters influence how we think and feel, and lacking certain amino acids can alter how these transmitters operate. Because the amino acid profiles of dairy proteins are different from meat and soy, you should try and get your daily protein intake from a variety of sources. For example, researchers found that the milk protein lactalbumin was very effective for stimulating serotonin synthesis while casein, another milk protein, had very little effect.

True Strength Moment: The essential amino acids might be crucial for muscle rebuilding, but the conditionally and nonessential amino acids have key roles in other important body functions. Including fish, meat, dairy and eggs in your diet will help cover your bases and maybe even contribute to a positive frame of mind for conquering physical goals.