The value of a ketogenic diet? To burn fat rather than just lose weight on the scale. Beginners at dieting often attempt to lose weight with short-term crash diets, which put the body in starvation mode and cause it to stockpile more fat as soon as possible (an evolutionary protection against times of famine). Conversely, the ketogenic diet puts the body into more of a sustainability mode, a stable way to reduce and optimize calorie intake, while focusing on foods that provide the essential amino acids for the ketogenic conversion of fat into energy.
So which ketogenic amino acids should you be eating, and where can you find them?
Amino Acids: the Fat Burning, the Sugar Forming, and the Switch Hitters
The building blocks of protein, amino acids can be categorized as exclusively ketogenic, exclusively glucogenic, or like Dr. Jekyll and Mr. Hyde: radically both. This is based on the end products produced during amino acid metabolism.
As you can see, the predominant category is the glucogenic group, with 13 amino acids. The carbon skeletons that result from the breakdown of glucogenic amino acids can be used via gluconeogenesis to synthesize glucose, simple sugar and an important energy source found in many carbohydrates. These are not the amino acids that will derive energy from your body's pre-existing fat stores.
The second largest category contains five amino acids, the switch hitters that when catabolized can yield both glucogenic and ketogenic products.
Acetyl CoA (the precursor of ketone bodies) and Acetoacetyl CoA are the first steps of the Krebs Cycle of energy production, which combines glycolysis and pyruvate oxidation with the citric acid cycle (which itself includes α-ketoglutarate, succinyl CoA, fumarate, and oxaloacetate—all byproducts of glucogenic amino acids). To access citrate synthase, the catalyst of this cycle, without glucose or carbohydrates is the value of ketogenic amino acids: it's like buying the product you need without bringing home any unnecessary or harmful packaging around it.
Acid Eater: the Amino Acids Essential to a Ketogenic Diet
Classes of amino acids can be further categorized as essential vs. nonessential, essential being the ones you must eat to obtain, and nonessential being those that naturally occur in the body, and are not reliant on the food you eat.
Nonessential amino acids:
- Glutamic acid
- Aspartic acid
Essential amino acids:
You may have noticed those last two are the exclusively ketogenic amino acids, meaning they only come from sources outside the body. Likewise, four out of five of the switch hitter or versatile amino acids are on this essential list as well, excluding only tyrosine, a conditional essential, as it's derived from phenylalanine (which is itself essential). Regardless of that particular debate, the core question remains: in what foods can the six essential ketogenic amino acids be found?
The Key Ingredients to Ketogenesis
Intro 101 of the keto diet is to go deeper when dieting, to the cellular level of biological sciences. This is more advanced than the grocery aisle surface choices people often make between low-carb and no-sugar-added options. It's important to remember that the colorful labeling on the front of food packages can often be subjective. It's better to know how to read the nutrition label with a keen (keto) eye.
Better yet, know what basic foods have the ketogenic keys to turn fatty acids into ketone bodies. These ketone bodies will then provide energy from your fat stores, without adding carbohydrates, and without impacting insulin or blood sugar levels. Here are where the six essential ketogenic amino acids reside.
Along with leucine and valine (glucogenic), isoleucine is an isomer (isolated form) of leucine that is one of the three branched-chain amino acids (BCAAs), all of which help to promote post-exercise muscle recovery. Involved in hemoglobin production, isoleucine can be found in:
- Protein sources like meat, fish, and eggs
- Dairy, particularly cottage cheese
- Seeds, grains, nuts, and beans including almonds, brown rice, cashews, lentils, and chia seeds
The source of tyrosine and one of the aromatic amino acids, phenylalanine is used in the biosynthesis of norepinephrine, dopamine, and thyroid hormones (huge players when it comes to mental health). Possibly effective in treating mood disorders, phenylalanine is contained in:
- Olives, figs, raisins, avocados, pumpkins, and most berries
- Meat, chicken, fish, and eggs
- Rice, beans, quinoa, and seeds
- Spirulina, seaweed, and leafy greens
An essential nutrient in the diet of vertebrates, threonine supports the central nervous system, along with the heart, liver, and immune system. A key component in the production of collagen, elastin, and muscle tissue, threonine can be gained from:
- Beans, nuts, lentils, and quinoa
- Lean beef, lamb, pork, and chicken/turkey
- Seafood including shellfish, particularly salmon, whelks, cuttlefish, octopus
- Seeds, including chia and hemp seeds
- Raisins, figs, avocados, and pumpkin
- Spirulina, watercress
Needed for nitrogen balance, tryptophan is also used to produce melatonin (for regulating sleep and wakefulness), niacin, and serotonin, the neurotransmitter known as the "happy" chemical. Tryptophan can be found in:
- Turkey (rather famously), as well as red meat, rabbit and goat meat, eggs, and fish
- Milk and cheese, particularly reduced fat mozzarella
- Pumpkin and squash seeds, along with chia, sesame, and sunflower seeds
- Almonds, peanuts, bananas, and chocolate (ideal ingredients for a sundae)
- Nuts, peas, beans, seeds, and pumpkins
- Chicken, beef, and pork
- Seafood including tuna
- Soybeans, whey protein, and plant proteins
- Cheese, particularly Parmesan
Necessary in the formation of collagen, connective tissue, and muscle growth and repair in the body, lysine can be found in:
- Protein sources like meat, poultry, seafood, and eggs
- Beans, peas, almonds, cashews, and chia seeds
- Spirulina, parsley
- Cheese and yogurt
- Whey protein
The Ketogenic Conclusion
You may have noticed some foods dominating the field; when it comes to essential amino acids for a ketogenic diet, where you find a good source of protein, you often find the ketogenic advantage. Donald K. Layman, Ph.D. along with Nancy R. Rodriguez, Ph.D. penned a paper for Nutrition Today titled "Egg Protein as a Source of Power, Strength, and Energy," but in it pointed out that egg is not the only food that packs that much value. With so many high-yield proteins, any dietary practice—be it vegetarian, vegan, kosher, or allergy-restrictive—can still gain you the essential amino acids for perfecting your ketogenic journey if you're diligent about ensuring your protein macros.
Your body is not so much a temple as a laboratory, a series of chemical reactions. Providing your body with the right ketogenic amino acids (instead of an overabundance of glucose precursors) sets you up for the ideal fat-burning catabolic pathways. This leads to healthy protein turnover for muscle growth, weight loss, and the energy to propel you forward.
Taking an essential amino acid supplement (which includes the ketogenic amino acids lysine and leucine) can help protect against any protein insufficiencies you may encounter while following dietary restrictions, such as the high-fat, moderate-protein requirements of the keto diet.