Ask the Diet Doctor: Why Is My Pee Bright Yellow?

This common effect of meal replacement drinks isn't cause for worry, but there are better things to drink


Q: Not to get too personal, but I've noticed that after I have my meal replacement shake (which is fortified with more than 100% of some vitamins and minerals), my pee is bright yellow. Should I worry?

A: No, you don't have anything to worry about. The reason your urine turns bright yellow after you have a meal replacement shake that is fortified with high levels of vitamins and minerals is because of the excessive amounts of vitamin B2 that your body does not need. Vitamin B2, or riboflavin, is a key component of cellular processes that involve energy production. Your pee turns yellow because the chemical structure of riboflavin get oxidized (a natural and required process). If you have ever taken a B-complex vitamin and noticed that it was orange-yellow in color, that is because of the riboflavin.

You may be concerned about excess riboflavin or other B vitamins, but there is no need for concern, as Bs are water-soluble and your body just gets rid of what it does not need when you go to the bathroom.

One things to consider regarding your fortified meal replacement shakes is can you fuel your body with better nutrition?

The convenience of meal replacement shake packets is hard to beat, but with that convenience you also get antiquated macronutrient ratios and poor quality carbohydrates.

Antiquated Macronutrient Ratios

Just about all meal replacement shakes follow the same formula: about 40 grams of protein, 20 to 25 grams of carbohydrates, 2 to 3 grams of fat, and 0 to 1 gram of fiber. This formula was made extremely popular in the 1990s with EAS's Myoplex shakes, but that was 20 years ago, we can do better. The lack of fat and fiber reduces your meal replacement shake's ability to mimic the satiety effects of an actual meal, and this is further reduced by the fact that liquid calories don't make you full. You also don't need more than 40 grams of protein and could do fine with 30 to 35 grams.

Poor Quality Carbohydrates

The primary carbohydrate source in most meal replacement shakes is maltodextrin. This is good from a food manufacturing standpoint, as maltodextrin is technically not a sugar so the label can read "low sugar," but maltodextrin acts essentially like glucose, causing large and fast increases in your blood sugar levels. This is not the ideal carb source if you are looking for a satiating meal replacement to accelerate weight loss.

If you can get over the convenience factor, then you are better off making your own meal replacement shake. Here is a simple recipe that you can make in a blender in less than five minutes. It will give you adequate protein, quality carbohydrates, fiber, and a blend of different fats, and it won't turn your pee yellow!

1 1/2 scoops vanilla whey protein isolate

1 cup blueberries

2 tablespoons walnuts

1 tablespoons chia seeds

1 to 1 1/2 cups unsweetened vanilla almond milk or water

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