In my younger days, I remember being obsessed with celebrity diets and exercise programs. How do they all stay so slim, fit and beautiful?
One particular interview with Britney Spears stuck with me for a while (circa-2005). The interviewer asked what she eats when hungry, particularly when on tour. The celebrity responded “canned tuna”, which was actually the snack of choice among female celebrities at the time.
If fat makes you fat, and sugar is bad for you, then the only alternative is protein. As I began to scale back my carbohydrate intake in 1999, I replaced those calories with more protein. Protein is satiating, and doesn’t spike your blood sugar as much a carbs do. But a lot of us have been conditioned to think of protein as a “free” food, which doesn’t contribute to weight gain. And that sentiment still prevails in some circles.
THE CONTROVERSY
We’ve already established that ketones can only be produced in the absence of insulin, and we all agree that carbohydrates release insulin. But the degree of insulin response from protein is much more variable.
At the heart of the problem is gluconeogenesis, a process by which glucose is produced from non-carbohydrate sources. It would appear that an individual’s metabolic health has a big impact on the amount of glycogen produced from protein.
Studies on the degree of insulin response from dietary protein are somewhat contradictory, leading to much disagreement among experts, particularly in the muscle-building community, where high-protein diets are commonplace. Even among the keto-adapted, eating too much protein can kick some people out of ketosis.
WHY DIETARY PROTEIN IS ESSENTIAL
You might be asking — why not just minimize protein intake to make sure remain in ketosis.
In short, some cells, such as red blood cells, can’t use fat for energy, and still require glucose. In the absence of carbohydrates, your body produces glucose from protein through gluconeogenesis. If you’re not eating enough protein through your diet, then your body starts to break down muscle tissue. This is the biggest criticism of long-term fasting, which some believe to be catabolic, leading to unwanted muscle loss.
Therefore, some amount of dietary protein is essential for muscle preservation.
WHAT WE ALL AGREE ON
It would appear that some people do get a large insulin response after consuming protein, while other see no change in blood sugar after eating a hefty steak dinner. The former is more commonly observed among diabetics and the highly insulin-resistant, while the latter is more typical among leaner, athletic, insulin-sensitive types.
So this brings us back to the question — how much protein should you eat every day?
FINDING YOUR LOWER LIMIT
Although there’s little consensus on how much protein is too much, we fortunately all agree on a lower limit, which is about 1.2 gram of protein per kg of total body weight. This is likely the minimum required to maintain and repair your muscles[1].
That’s not a lot of protein, certainly a lot of less than most people eat. As an example, if you weight 140 lbs (64 kg), that works out to about 75 grams per day. Split into three meals, that’s only 25 grams per meal. That’s equivalent to one can of tuna, a 3½ oz steak (100 g), or half a chicken breast, assuming no other protein sources in your diet.
I don’t know anyone who eats a 3½ oz steak for dinner, or half a chicken breast. I certainly didn’t.
FINDING YOUR UPPER LIMIT
The upper limit is little more fuzzy, although most would agree anything above 2 grams per kg is probably excessive. For that same 140 lb person, 2 g/kg is 130 grams of protein per day, which is quite generous in my opinion.
Some would argue 2 g/kg is way too much, while others maintain more is better, particularly die-hard carnivores and those in the weightlifting community. Traditionally, protein requirements were thought to be a function of lean body mass, although that theory is also up for debate.
Before you get all excited and pick the maximum daily allowance, note that there’s a lot of conflicting data on this subject. As previously noted, too much protein can kick some people of out ketosis, particularly for those who are insulin resistant. Also note that 2 g/kg of bodyweight is more than double government guidelines[2].
MY EXPERIENCE
Pre-keto, I ate about 130 grams per day of protein, most of that was “meat” — predominantly chicken and pork (my intake of nuts and cheese was minimal at the time). Following the advice of Phinney and Volek, I decided to cut my protein intake in half, just 75 g/day, which worked out to about 1.3 g/kg of body weight.
As noted in a previous post, reducing my protein intake proved to be much more difficult than I thought. While I was careful to slowly reduce my carbs over the span of a few months, I literally slashed my protein intake in half almost overnight. I went through the dreaded keto-flu, leaving me feeling extra-tired and super-cranky for about two weeks. There’s no doubt in my mind that my body was producing glycogen from protein, probably because my carb intake was insufficient to meet my daily energy requirements, and I was certainly not producing ketones.
I have stuck with about 75 g/day since the end of 2015, and haven’t changed my protein intake despite big changes in my body composition. At my current bodyweight, I now eat about 1.5 grams of protein per kg of body weight.
It’s worthwhile to note that accurate protein measurement can be very difficult for some cuts of meat, particularly pork, beef, lamb and sausages. The percentage of fat and protein varies greatly by cut and quality, so my numbers might drift way over or way under on some days. However, I’m confident I’m usually below 1.7 g/kg, and that certainly isn’t enough to kick me out of ketosis.
WHERE TO BEGIN
A good place to start is 1.5 grams per kilo of body weight, which is right about average for most people. This is considered a moderate-protein intake, and should be low enough to ensure the production of ketones (assuming carb intake is sufficiently low).
I always recommend people baseline their starting points pre-keto. If you’re making a drastic change, don’t be surprised to experience withdrawal symptoms. If accurate protein measurement is important to you, I recommend sticking to lean meats, like boneless/skinless chicken breast or tuna. Be sure to distinguish between raw weight and cooked weight when logging meals into your food tracker. Cooked meat is much higher in protein due to water content.
Remember that dairy products, eggs and cheese are major sources of protein. Nuts, seeds, chocolate and even some vegetables also add to the bottom line. So don’t be surprised if your daily intake of “meat” is much less than what you’re used to.
THE NEXT STEP
Once you figure out how much carbs and protein to eat every day, the next step is to set a daily fat allowance.
NOTES:
1 The folks at Virta Health have a more technical explanation, found here.
2 Shockingly, government guidelines for daily protein intake is only 50 grams for an average sized person. This is based on their stance that meat is unhealthy, particularly red meat, and should be avoided as much as possible. The government still frowns upon saturated fats, which means also minimizing cheese, eggs, nuts and full-fat dairy products, four other main sources of protein.