Should I meet nutritional recommendations (for e.g., RDAs) daily?

Question

For example, the recommended daily protein intake is 0.8g per kilogram of body weight. So, let's say that I take more than required on a given day and less than required on an another day -- is that okay? I'm not asking about eating all the protein you need one day and nothing at all for the rest of week, but what about tiny fluctuations? What if you meet 50% of your daily recommendation one day but compensate for it the next couple of days?

How does that work for other nutrients such as vitamins and minerals? Does our body somehow 'store' these nutrients when you take in more than what is necessary?

Answer 1

In short: For most nutrients, you do not need to meet the Recommended Dietary Allowances (RDAs) each day. You could get, for example, 7 RDAs amounts of certain nutrients randomly distributed through 7 days without having any deficiency symptoms.

Office of Dietary Supplements, NIH.gov:

Recommended Dietary Allowance (RDA): average daily level of intake sufficient to meet the nutrient requirements of nearly all (97%-98%) healthy people.

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1) Compensatory mechanisms that can provide the sufficient amount of nutrients on the days you don't get them by food:

• The release of nutrients from your body stores (glucose from glycogen in the liver, fat from body fat, proteins from liver and blood proteins, vitamins from the liver, calcium and phosphorus from bone, etc.)
• The conversion of carbohydrates, proteins and fats into each other in your body
• Retaining minerals, such as potassium, by the kidneys

2) For how long can you skip the intake of a certain nutrient without having any deficiency symptoms?

• Carbohydrate stores (in the form of glycogen) last for 1-2 days after you stop consuming them. After that, carbohydrates can be produced in your body from fats and proteins. Theoretically, you do not need to get any carbohydrates from food for any period of time because they can be all produced in your body.
• Proteins in the liver and blood represent an amino acid pool, which can be used to create new proteins, as needed, for at least few days after stopping consuming proteins.
• For how long you can go without fats, mainly depends on your body fat stores as mentioned in this 382 days fasting study.
• The stores of water-soluble vitamins (B complex, C) should be enough for 1-2 months, in most cases, but vitamin B1 stores could last for only 2-3 weeks.
• The stores of vitamins A, B12 and E could be enough for 2 years or more.
• You could probably go without most minerals for at least 1 month according to the abovementioned fasting study.