Are Vitamins Lost during Meal Prep?
Meal prep has been receiving a lot of traction online, on social media, and in my household. I rely on meal prep days to get me through the week to enjoy healthy, tasty meals and not have to stress about planning a last-minute menu, which is when I am most likely to cave and say, "the heck with it, let's order some pizza."
But here is the big question, is all of this hard work pre-cooking, pre-chopping, portioning out etc., actually robbing your body of precious vitamins? An excellent question but a somewhat complicated answer as not much research has been performed on the longevity of nutrients in the foods we prepare. So let's take a second to review the information we do have.
Cooking vs. Raw
When it comes to raw vs. cooked vegetables, fruits, grains, fats, etc., raw almost always wins when providing our bodies with the biggest bang for our buck. Most vitamins, minerals and fats are denatured (modified or destroyed) by heat, light and air. It is pretty safe to assume that raw will almost always give your body more of what it needs, so be sure to incorporate raw fruits and vegetables into your diet.
This "rule" does not hold up when we are talking about spinach and calcium. Spinach, like most greens, contains a compound called oxalate or oxalic acid. Oxalates have been linked to kidney stones; they also block the body's ability to absorb calcium from our greens. The good news is that once you saute, steam or blanch that spinach, the heat breaks down the oxalates making calcium much more available for our body to absorb. For example, 100g of raw spinach contains about 10% or 99mg of our required daily intake of calcium, but just a few minutes overheat, and that same 100g of spinach now has 14% (136mg) of our daily intake of calcium.
Although raw, whole and natural foods are often best, sometimes it is good to know that when it comes to certain vegetables and other foods like meats, fish and poultry, it is just beneficial to cook them. Additionally, whether you're eating your vegetables raw or cooked, the critical part here is that you are eating vegetables, so don't get too wrapped up in a game of good vs. bad.
Storage Methods - Can it Help with Longevity?
Food storage, now this is a bit tricky. All foods have different, let's call them, "shelf lives." Red meat will last longer cooked or raw in your fridge than say fish would, raw carrots will last longer than cooked, and rice will likely last longer than oatmeal, but how long is too long, and what can you do to preserve your foods to avoid food waste and losing those precious nutrients?
We are talking about prepared food here, so I will quickly mention that unprepared, whole foods (i.e. a full carrot as opposed to prepared carrot sticks) will last much longer and retain nutrients longer than their cooked counterparts.
When possible, using air-tight containers and glass helps maintain the freshness of cooked and prepared foods and makes it easier to toss in the oven or microwave and reheat. Plastic containers (hopefully BPA-free) are great here, too; I would recommend trying to avoid reheating in them when possible. These containers don't need to be fancy (think old pickle jar or previously used a mason jar), but sealing fully is important.
Additionally, small things such as storing pre-chopped and peeled vegetables in a bit of water will help protect them from bacteria and keep them crispy longer. Storing grains in shallow dishes and allowing them to cool completely to reduce potential condensation will help them stay fresh longer.
So, in short, yes, there are ways to store our foods (sealed container instead of open to the elements) will aid them in lasting longer, so check your food prep containers, make sure they fully seal and allow your food to cool off before storing it in the fridge.
Is there still a benefit to Meal Prepping?
Okay, so we know raw is often more robust when it comes to nutrient density and that everything has a shelf life, so it comes down to whether or not meal prepping is even worth it.
It takes time to get used to, you have to set aside time to make your food, and then at the end of the day, you might not even be getting the good vitamins and minerals you were hoping to because the food is too old!
A few studies have been done on this with fruits and vegetables to see if we are robbing ourselves of nutrients in an attempt to be food prepared for the week. The majority of the studies roughly concluded to tell us the same thing. One of the significant take-aways is that the more processed (I don't mean packaged foods), by processed I mean prepared (chopped, diced, steamed, baked, broiled, boiled, blanched, etc.) by you in the kitchen food is the faster it is likely to lose its nutrient integrity.
For example: cold press juice vs. lightly steamed spinach. After a day of the juice being made, it will retain up to 80% of the whole original nutrients, and 3-5 days later, it will be a shell of itself containing about 20% of its original vitamins. On the other hand, steamed spinach will retain 53% of its nutrients 8 days after the steaming. You probably don't want to eat 8-day old steamed spinach for other reasons, but the vitamins and minerals are there.
This example demonstrates that how we prepare our food will also affect how long/beneficial our food will be. Methods such as sauteing have been shown to improve our absorption of fat-soluble vitamins (A, D, E, K) due to using a fat while cooking, roasting and steaming because of their lower temperatures are less likely to destroy nutrients. In contrast, methods such as frying are likely to do the opposite.
So, what am I rambling on about?
I have been rambling on for a while without providing you with any definitive yes' or no's, so here is a quick summary.
Yes, cooking, peeling, chopping and preparing your food will destroy some vitamins, minerals and reduce overall water content.
Yes, raw is better sometimes, but just because it is sometimes more nutrient-rich doesn't mean it is always the best option, i.e. you probably want warm food in the winter, so you don't freeze.
No, your food will not last forever; 3-5 days is probably your sweet spot. So, if you are currently making 7 days worth of food, I would urge you to reconsider. Not only is the nutrient density of your food pretty weak by the end of the week, but you are also getting into food danger zones and can potentially make yourself sick.
Yes, some cooking methods will help with vitamin and mineral absorption.
No, you should not stop meal prepping. It is a huge time saver, and it is often the difference between you eating vegetables and potentially just having popcorn for dinner.
