“Can I use Slimfast® or those Premier Protein® shakes as part of my weight loss plan?”
This question invariably pops up during our Obesity Medicine consultations with patients. The answer depends on your situation and how low a calorie plan you choose, but the simple answer is no, they are not part of a medical weight loss plan.
At the surface, the labels of consumer available protein shakes look very similar to medical grade products such as OPTIFAST®. They have lots of protein, don’t have excess carbs or fat, and have several vitamins and minerals. These types of protein shakes are acceptable to use when you are replacing a meal or a snack. However, when you try to replace your entire daily intake and get your entire nutrition from an over the counter shake, you will be missing some very important nutrients and may get ill.
For example, you won’t get enough potassium with five Premier Protein® (70% of your RDA) or five Slimfast® shakes (85% of your RDA). This will result in a drop in your serum potassium levels, leading to the risk of potentially fatal heart arrhythmias or muscle weakness.
The same is true for sodium intake. Premier Protein® only supplies 70% of your RDA. When you lose weight, you also dump lots of sodium through the kidneys. As a result, you can develop dangerous brain swelling from hyponatremia. Slimfast® has even lower sodium content, providing only 45% of your RDA on five a day.
When placing a patient on a diet lower than 1000 calories or when replacing your entire intake with meal replacements, it is critical that you monitor your kidney and liver function, and electrolyte levels.