What is Protein?

Protein is one of the key macro-nutrients essential for the body's development, recovery and sustainability. It is made up of amino acids that the body uses to build and repair tissues.

The body can naturally produce 11 of the 20 amino acids it needs. They are known as nonessential amino acids and they are alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, proline, serine, and tyrosine.

The remaining amino acids are known as essential amino acids and must come from your diet.They are histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine

Complete vs. Incomplete Proteins

Complete Proteins
Complete proteins contain all nine essential amino acids. They are mostly found in animal products, although some plant sources also qualify.

Examples of Complete Protein Sources:

· Fish

· Meat

· Eggs

· Dairy

· Quinoa

· Soy

Incomplete Proteins
Incomplete proteins lack one or more essential amino acids. However, combining different incomplete protein sources can provide all essential amino acids.

Examples of Protein Combining:

· Rice and beans

· Peanut butter on whole wheat toast

· Hummus with pita bread

What is the Ideal Protein Intake?

The recommended daily protein intake, according to the Dietary Guidelines for Americans (2020–2050), is:

· 0.8 g/kg (0.36 g/lb) of body weight for adults

· 1.5 g/kg (0.68 g/lb) of body weight for children

· 1.0 g/kg (0.45 g/lb) of body weight for adolescents

Recent research suggests that 1.2–1.6 g/kg (0.54–0.73 g/lb) of body weight is ideal for most adults. Harvard Health recommends that non-athletes limit their protein intake to a maximum of 2 g/kg (0.91 g/lb) of body weight daily.

Note: These recommendations are based on individuals with a healthy BMI. For those who are overweight, protein calculations should use adjusted body weight.

Are All Proteins Created Equal?

No, not all proteins are created equal. The quality of protein varies depending on its amino acid content and bio-availability (how efficiently the body can use it).

Animal proteins are generally superior in terms of bio-availability and essential amino acid content. However, with careful meal planning, plant-based diets can also provide all essential amino acids.

What is Considered Over-consumption of Protein?

Protein over-consumption refers to exceeding the safe upper limit for protein intake. For non-athletes, Harvard Medical School advises limiting protein to 2 g/kg (0.91 g/lb) of body weight daily.

Effects of Protein Over-consumption

A study titled "Adverse Effects Associated with Protein Intake Above the Recommended Dietary Allowance for Adults" provides evidence of the long-term risks of excessive protein consumption. A diet high in protein, generates a large amount of acid in the body coming from the break down of protein into simple amino acid.The kidneys which are one of the primary excretory organs in the body is responsible for excreting this acid and consequently the skeleton offers a buffer for this acid excretion leading to active re-absorption of calcium from the bones thus leading to calcium loss and after long periods of time it can lead to a condition known as Osteopenia

To add onto that the calcium re-absorption from excessive renal acid excretion leads to excess calcium in urine a condition known as hypercalciuria. The calcium could then lead to the formation of kidney stones if accompanied by a low fluid intake diet.

Some other adverse effects of protein over-consumption include:

· Cardiovascular diseases

· Seizures

· Weight gain

· Acne

· Cancer

· Type 2 diabetes

What Happens to Excess Protein?

When protein intake exceeds the body’s needs:

· Excess protein is often stored as fat.

· Amino acids are excreted through urine as ammonia

Signs and Symptoms of Protein Over-consumption

· Nausea

· Fatigue

· Diarrhea

· Abdominal discomfort

· Headache

Who Should Avoid High-Protein Diets?

1. People with Kidney Issues
According to Dr. Howard E. LeWine, Chief Medical Editor at Harvard Health, individuals with kidney disease or a history of kidney stones should avoid high-protein diets.

2. People with Cardiovascular Conditions
High-meat diets, which are often protein-heavy, can increase the risk of coronary heart disease due to saturated fats and cholesterol.

Key Takeaways

· Complete proteins provide all essential amino acids, while incomplete proteins do not.

· Combining incomplete proteins can ensure adequate amino acid intake (e.g., rice and beans).

· For most adults, aim for 0.8–2 g/kg (0.36–0.91 g/lb) of body weight daily.

· Individuals with kidney or heart issues should consult a doctor before starting a high-protein diet.

· Protein needs vary based on age, gender, and activity level.

Read more about:

Hypertrophy and Strenghth Training

Different Types of Diets

Disclaimer:

No content on this site, regardless of date, should ever be used as a substitute for direct medical advice from your doctor or other qualified clinician.