If you hit a wall when it comes to building muscle, it could mean you aren't getting enough protein.
Getting the sniffles or feeling under the weather all the time could mean that your immune system isn't working as well as it should because you aren't eating enough protein.
Your body has to find a way to get amino acids when you don't eat enough protein. To get the protein it needs, it starts to break down your muscle mass.
Protein is the most satiating macronutrient, which means it makes you feel full longer and lowers your cravings.
A protein shortage impacting neurotransmitter synthesis may cause mood swings. Neurotransmitters help brain cells communicate for mood balance.
Protein deficiency can cause anemia, which is commonly linked to iron.Iron deficiency can take numerous forms, but hypoproteinemia is a low blood protein level.
It's possible that not getting enough protein is stopping you from losing weight if the scale won't move.