Ask anyone and most people will tell you that protein is key to a healthy diet. It fills you up, is converted and used to build and maintain muscle, and is a good source of vitamins and minerals. We by no means will argue with that. Yet when it comes to a ketogenic diet, which by definition is a low carbohydrate, moderately low protein, high fat diet, you need to monitor your intake and consume the proper amount to meet your body’s nutritional needs while maintaining ketosis.
So how do you know what your body needs? This is where proper macronutrients, or macros, play a large role in success. When using an online macro calculator you want to look for one that takes into account both your body fat percentage as well as your activity level. This is important because the amount of protein you’ll need is based on maintain the muscle you currently have and building new muscle while you exercise.
In the example below, woman A would require more calories and protein then woman B due to her more vigorous activity level. During her workout, her heart rate is elevated for at least 30 consecutive minutes and that’s what you need to be doing to require more protein to fuel your workout, maintain and build muscle, as well as provide the nutrients needed to sustain your body.
Woman A: 5’7 165lbs, weight lifts daily for an hour a day, and does 30 mins of cardio every other day.
Woman B: 5’7 165lbs, active with her children, and walks 1-2 miles a day.
So what happens when you have too much protein? Well, when eating a well formulated ketogenic diet, you are depriving yourself (intentionally, of course) of glucose. This is done to force your body to rely on fat for energy. This means your stored fat (aka, adipose tissue), your ingested fats, and your self-generated fats (cholesterol). When you are depriving yourself of excess glucose to be used as energy and stored as fat, your body will look to utilize other macronutrients in its place. With protein, this can become a problem. Unlike lipids (fats), protein converts more easily into glucose through a process known as gluconeogenesis.
Gluconeogenesis is the process of turning non-carbohydrate sources (protein in this case) into glucose to be used to meet the body’s energy need (Mosby, 2009). Protein is the first thing the body is likely to convert. So to answer the question, “what happens when you have too much protein?”… it turns into sugar! That is the exact situation you are trying to avoid on the ketogenic diet as this increases your risk for further storage of glucose as fat and reduces reliance on stored fat to be burned (causing a weight loss stall).
“But I read somewhere that I should eat less fat so that my body burns the fat I currently have”. This is something we hear often, unfortunately, it is just not true. So what’s the real answer? You have to train your body to utilize fats for its primary caloric resource. That is the entire premise behind the ketogenic diet… use fatty acids (ketone bodies, stored fat, ingested fat, and generated lipids) for fuel in place of glucose or protein being turned into glucose. To fully understand this, you need to understand the topic of macronutrient breakdown.
Your macronutrients are broken down into two tiers: 1) Calories, 2) Fats, Protein, and Carbohydrates. The second tier is a subgroup of the first, meaning that your calories are just the total number of energy units gained from the foods you eat. You then break that down by grams per macronutrient (x grams of fat, x grams of protein, and x grams of carbohydrates). These values need to be individually determined, although many keto dieters practice the method of 20g of net carbohydrates per day. This allows you to get in vital micronutrients and fiber while avoiding things that will turn to glucose and cause an insulin spike. If you break this down into percentages (for the sake of discussion), rather than grams per macronutrient, the highest percentage should be fat intake. This is to train your body to rely on fats as your primary fuel source. The next highest is protein, followed by carbohydrates as the lowest. Again, the values assigned to each of these is individually specific and influenced by a number of things such as activity level, body fat percentage, age, current weight, gender, desired metabolic benefits (weight loss, weight maintenance, muscle gain, etc), and even some pre-existing medical conditions.
So to wrap up the issues with the aforementioned statement, “I should eat less fat so my body will burn more,” it is not as simple as calories in, calories out or grams of fat in, grams of fat burned. Fat is utilized in a number of ways by the body and calories are also burned for a number of reasons. Tasks as trivial as breathing utilize calories. Where those calories come from makes all the difference. If you are not ingesting fat, your calories have to come from somewhere else. If your calories are coming from protein, it can be turned into glucose and slow or even halt the process of burning fat as well as kick you out of ketosis. If they are coming from carbohydrates, then (simply put) you’re not ketogenic. If they’re coming from fat and you have calculated your actual metabolic needs correctly, you will burn stored fat and you should not restrict your ingested fats to do so. A ketone monitor can also come in handy to fine tune your macros to ensure you are staying in ketosis and can see how different meals/foods affect your personal levels. Everyone is unique and responds differently so it’s important to adjust your nutritional plan so it works for you and your body’s needs
glyconeogenesis. (n.d.) Mosby's Medical Dictionary, 8th edition. (2009). Retrieved May 31 2018 from https://medical-dictionary.thefreedictionary.com/glyconeogenesis