Protein contains only around 4kcal per gramme. It is the least calorific macro-nutrient.
How much protein is too much protein? What happens if we consume too little or too much? These are typical questions you will ask when you start a ketogenic diet.
20 different amino acids made up long chains that we call proteins. Proteins are used to maintain tendons, ligaments, bone (it’s not just calcium), skin, muscles, and most of our internal organs, and blood vessels. Proteins also travel around our body in the form of hormones (such as insulin). We need a constant supply of protein as our body requires continuous repair.
Many westerners consume too much dietary protein. Unless we are undergoing heavy training, we only require around 0.8g per kilogram body mass to maintain our weight (i.e. if you weigh 100kg then you only need to eat around 80g of protein). The bodybuilding and athletic community however, seems to suggest that under heavy training this value could be doubled. Personally I tend to consume around 1 to 1.2g per kg as I usually do around an hour of cardio and an hour of walking a day.
There are various online protein calculators available like this one.
Not consuming enough protein
If we do not consume enough protein, then our body with catabolyse (recycle) our less critical tissues – usually our skeletal muscles – in order to maintain vital organs. This is why people who have been starved are all ‘skin and bone’. This doesn’t happen overnight, though, and a long term deficiency will cause:
- Fatigue – symptoms of lethargy and weakness will become apparent, making it hard to exercise.
- Gastrointestinal problems – protein deficiency will cause the stomach to produce less acid. This can make it harder to absorb various minerals such as potassium and phosphorus, and can lead to diarrhoea, further complicating issues.
- Immune deficiency – our immune system relies on our antibodies to deal with unwanted invaders, and antibodies are made of – yep, you guessed it – protein.
People on a ketogenic diet are usually meat eaters, so are seldom at risk of low protein or being unable to obtain all of the required amino acids from their diet. However, vegetarians should take steps to ensure they are receiving all essential amino acids (foods like quinnoa supply all nine of the essential amino acids we require).
Consuming too much protein
Excess protein goes through the process of gluconeogenesis whereby it is converted to glucose, and subsequently via glycogenesis to glycogen for storage in muscle cells or in your liver (which will then send it on to your adipose tissue) – this in turn tends to raise insulin levels, and may contribute to insulin resistance. As the whole point of a Ketogenic diet is to reduce our blood insulin, we certainly don’t want to convert meaty goodness into sugar! This is reason enough for me to watch my protein intake carefully.
It is generally accepted that if you are consuming more than 30% of your daily energy intake as protein then you are likely to start feeling unwell. A 1920s study carried out at Bellevue Hospital in New York subjected the researcher anthropologist Vilhjalmur Stefansson to high protein for a few weeks and he reported feeling sick to his stomach.
There has been some interesting research in terms of the damaging effects of too much protein:
- Calcium loss – Ingesting too much protein was believed to cause a loss of bone strength due to the increased excretion of calcium in the urine. However, it is now known that increased protein also causes increased absorption of calcium from the small intestine, which may be greater than the excreted amount – which may help maintain bone health as people age.
- Renal dysfunction – Again, it was thought for many years that high protein diets might cause or contribute to kidney failure. However, well over 100’000 people in the US live with only one kidney, and over a three year period, only 65 developed kidney failure (a rate that was lower than the national average – oddly) – so there is little to suggest that a modest ‘overdose’ of protein presents any danger to kidney function.
Another important factor for not consuming too much protein is that it’s expensive to buy.
How do I know how much protein I am eating?