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How Long Will Whey Keep? | Ask The Fitness Nerd

How Long Does Whey Protein Last For? We Take A Look At The Shelf Life of That Cannister of Whey Protein

Dear Fitness Nerd,

I have a quick question about the shelf life of whey protein powder.  My ex boyfriend left a 5lb tub of Optimum Nutrition 100% whey protein powder in our apartment, but I can’t seem to find an expiration date on it. We’ve been broke up for about a year, so I know it’s at least 12 months old. It still has the seal on it, so I think he may have bought it right before we split. Is it safe to use? And do you have any idea how long it will keep?  Thanks! –  Tasha (Las Vegas, NV)

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What Is A Complete Protein? Complete vs Incomplete Proteins | Ask The Fitness Nerd

Completely Confused About Complete Proteins? Learn What A Complete Protein Is and How Balance Your Protein Intake

Dear Fitness Nerd,

Can you explain exactly what a complete protein is? I’m 23 and pretty into fitness, working out, etc. I lift weights several times a week and run daily.  But I’m also a vegetarian and concerned I may not be eating enough protein every day to support my activity levels.  I’m also worried that since I primarily eat plant sources of protein, I might not be getting a complete protein. Can you help me out here? Thanks!   – Jessa (San Diego - CA)

A complete protein is a protein source that contains all eight essential amino acids in the sufficient proportions to support normal biological functions.   In adults, the eight essential amino acids are:

• Phenylalanine
• Valine
• Threonine
• Tryptophan
• Isoleucine
• Methionine
• Leucine
• Lysine

These amino acids are called “essential” because the body cannot make them, so they have to be supplied through diet.  Recently, histadine has been added to this list as well, as scientists discovered that adults cannot synthesize it.

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Does Whey Have Casein? | Ask The Fitness Nerd

Does Whey Protein Also Contain Casein? We Sort Out The Milk Protein Mystery Once and For All.

Dear Fitness Nerd,

I’m a little confused about whey and casein protein. Does whey also contain casein? And vice versa?  All I know is that both whey and casein are in milk.  Can you help me sort this out? — Janine (Dunwoody, GA)

You’re right that both whey and casein are proteins in milk.

But the important thing to grasp is that they are two totally different kinds of protein.

So in their purest form – isolated from the milk itself (for example in protein powder supplements) — whey typically doesn’t contain meaningful amounts of casein. Same goes for casein in regards to whey content.

Understanding Milk Proteins: Whey vs. Casein

The easist way to think about this is in the context of milk.

Milk contains about 80 percent casein protein, and 20 percent whey. Under normal conditions, you would never be able to differentiate between the whey and casein in milk visually. It just looks … well … liquid and “milky.”

However, when you add an acid or enzyme like rennet (which is used in cheese production), the milk will curdle. This literally separates the whey from the casein proteins.

The result is that the whey — which is a semi-clear liquid — will rise to the top, while the casein (which is heavier and coagulates in the presence of an acid or enzyme) will usually sink to the bottom.

In cheesemaking, the whey is siphoned off from the casein, and the solids are then drained through a cheese cloth, further extracting any residual whey or water and leaving the firm casein solids, which are then shaped into blocks of cheese (there are more steps, but I won’t get into them here.) 

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