Side effects of protein

As noted in previous articles, in every discussion about macronutrients, they all refer to the amounts of carbohydrates and fat, as well as to “good” or “bad” carbohydrates and “good” or “bad” fat. However, when it comes to protein, the discussion stops and everyone agrees, the more protein you consume, the better you will get. But what are the side effects of protein?

Surely a protein-rich diet will help you lose weight and is a diet that is being discussed and recommended by many nutritionists. And because carbohydrates are accused of being responsible for diabetes, then definitely a diet with few carbohydrates and a lot of protein is the best option for diabetics. Or not?

Research shows that if you suffer from insulin resistance or are diabetic, taking large amounts of protein (such as Whey, which gives you high amount per shake) may potentially aggravate your problem.

Note that as a high amount of protein it is considered to ingest more than 35% of your total calories. For example, if you consume 2000 calories, 35% is 175g protein per day [1] and if you drink 2-3 shakes a day, along with the protein you receive from the rest of your diet, then 175g is a number that is easily exceeded.

Consuming large amounts of protein can increase plasma glucose and insulin levels, reduce insulin sensitivity and cause diabetes [2, 3, 4, 5, 6], especially when eating low carbohydrate and high animal protein [7, 8].

Also, consuming large amounts of animal protein increases microalbuminuria, which is considered as an indication of onset diabetic nephropathy [9], and can also suppress your liver (since it will process it) lead to an increase in the blood amino acid concentration. Also cause nausea or diarrhea and in excessive amounts, cancer and even death, according to an article published in the International Journal of Sports Nutrition and Exercise Metabolism [10, 11].

In fact, researchers have been examining the effect of the protein on gluconeogenesis, glucose synthesis from non-carbohydrate sources, such as a study examining glucagon and insulin levels after consumption of various protein sources [12].

Their results (image below) showed that even in healthy people, 25g of glucose with 30g of protein (Whey-WPH, Pea-PPH) cause too much increase in plasma glucose and glucagon (and therefore gluconeogenesis) in just 20min of its consumption.

This is important because in people with type 2 diabetes (or insulin resistance) where the body has insulin resistance and can not stop gluconeogenesis, resulting in high blood sugar. Under normal circumstances and when there is no insulin resistance, insulin stops the action of glucagon and thus prevents the release of more sugar in the blood [13].

Certainly there are opposing opinions, but are not based on the same protein sources. For example, in one study, 50g of protein did not show a high blood glucose concentration [14]. However, in that study they used beef, a source of slow-absorbing protein rather than fast, such as Whey, which was used in the above study.

Of course I do not say to not consume any protein or that protein is not necessary and one should not use shakes after his workout. However, if you suffer from diabetes or insulin resistance (and certainly many people who do not exercise for a while or do not care for their diet, have a form of insulin resistance), you should be careful with the amounts of protein you consume, because as you will see, large amounts does not necessarily make good, and animal protein in general has also been linked to cancer. Even after intense weight training, the amount of protein needed for muscle protein synthesis and repair is 20g [15].

It is also good to limit whey protein or replace it with other sources, such as peanut, rice or vegetable protein supplements. You can also consume vegetables, fruits, pulses and cereals to avoid excessive consumption of poultry and meat and make sure you get all the essential amino acids [16].