Depends on the food, but...
Raw food ingredients and cooked ingredients have a lot of differences in their chemical composition and nutritional value.Once cooked, the nutrient value of the meal doesn’t stay the same as when it was raw. Because prepared meals do lose nutrients, for instance, vitamin C-rich foods red bell pepper, and potatoes break down a little when surrounded by heat.
Research also demonstrates that vitamin C retention ranged from 0.0 to 91.1% for all cooking methods.[i]
Another research was done to see the nutrient loss of foods. The results showed that boiling spinach, peas, green beans and okra without thawing resulted in 46.5, 25.2, 18.2, and 21.6% vitamin C loss.
Food will lose nutrients no matter what; it doesn’t matter whether the foods are prepared before eating time or made fresh.
Does reheating food in the microwave kill off nutrients?
Well, turns out microwave isn’t the villain everyone thought it to be!
The nutrients lost while cooking/preparing depend on cooking methods and time. For example, the longer a food is cooked, the greater the loss of nutrients.
Meaning, that additional reheating can make the nutrients and flavour run out after reheating again and again.
According to research, the mineral contents of cooked foods in mass cooking are 60-70% of those in raw or uncooked foods. [ii]
What To Do To Minimise The Loss Of Nutrients In Prepared Meals?
These 6 key points avoid nutrient loss during cooking, storing, and refrigerating.
1. Use The Best Tool and Method for Reheating:
The way you reheat your food impacts the taste and nutrition content of that food significantly. If you order some liquid ready-made meals such as soup and stews; heat them on the stove, and bring them to boil while stirring frequently.
Similarly, for dry and roasted meals, reheating them in the oven.
Moreover, wrap your ready-made meals with an aluminium paper to save the nutrients; the protein molecules present in foods can tighten when exposed to heat directly and causes water, fat, and other nutrients to force out.
2. Don’t Throw Away Liquids!
When you reheat a veggie/meat, there’s always some excess oil, grease, water, or any liquid left in the container. That liquid/juice contains plenty of nutrients from that food.
Please don’t waste it! Spill it on the food when eating it.
High-quality companies and restaurants make sure they save and pour the liquid on foods as they know all the taste and nutrients lie on it!
3. Prefer UnpeeledVegetables/Fruits
The debate on whether to peel or not to peel veggies and fruits is still ongoing. However, that USDA shows precise results that unpeeled vegetables/fruits are nutritionally better.
For instance, apples with skin have more vitamin K, vitamin C, vitamin A, calcium, and potassium levels than those without skin.
4. Order Whole Cooked Meals
Having uncut meals can save your meal from nutrient loss. You can order your food whole, then cut it when plating or eating. On The Meal Prep Market there are meal preppers who sell bulk bags of whole pieces of meat and whole veggies such as broccoli.
In a 2016 Cambridge study, researchers tested carrots for the number of polyacetylenes. [iii] Polyacetylenes in carrots are involved in anti-inflammatory and anti fungal activity in humans. The carrots were boiled in different forms, such as a cut in disks and batons, and kept whole too. The cooked whole carrots had the most number of polyacetylenes present in them.
Similarly, for other food ingredients, meals will do lose nutrients but less when their whole.
5. The Art of Undercooking!
High-end ready-made meal companies know the basics of how to keep the nutrients in food! They’ll have your meals a little undercooked; here are the reasons why.
First, the lesser the cooking duration, the lower the nutrients lost. Secondly, when you reheat your prepped meals or ready-made meals, it has a low chance of being soggy or dry.
6. Store Them Accordingly
When ordering meal prepping, make a plan when to eat which food. Some foods such as meat and poultry can stay in the refrigerator for around 3 days.
However, they can stay good for more than a week in the freezer. Make sure to store cooked and prepared meals according to your needs.
Which Foods Should be consumed As Soon As Possible?
Some ingredients lose their freshness, taste, smell, and texture more quickly. Following are such foods listed that should be prioritised to be eaten fresh.
Most Common Foods And Their Lives in the Fridge at good nutritional levels
- Chicken/Turkey ------ 4 days
- Fish ------ 4 to 6 days
- Broth ------ 3 days
- Hard-boiled eggs ------ 1 week
- Salads ------ 2 to 4 days
- Asparagus ------ 4 to 7 days
- Broccoli ------ 4 to 7 days
- Cucumbers ------ 1 week
- Peppers ------ 1 to 2 weeks
- Spinach ------ 3 to 5 days
- Sprouts ------ 3 to 5 days
The bottom line:
Prepped meals do lose nutrients one way or another. However, there are various methods to minimise nutrients loss. `Meal Prep companies are really careful not only about macros but also micronutrients and so strive for maximum nutrient retention.
[i] Lee, S., Choi, Y.,Jeong, H. S., Lee, J., & Sung, J. (2018). Effect of different cookingmethods on the content of vitamins and true retention in selectedvegetables. Food science and biotechnology, 27(2), 333-342.
[ii] Kimura, M., &ITOKAWA, Y. (1990). Cooking losses of minerals in foods and its nutritionalsignificance. Journal of Nutritional Science andVitaminology, 36(4-SupplementI), S25-S33.
[iii] Warner, S., Seal, C., Haldar, S., & Brandt, K.(2016). Retention of polyacetylenes and carotenoids in carrot duringcooking. Proceedings of the Nutrition Society, 75(OCE2).