Adipose tissue: the tissue that stores energy as fats/lipid droplets inside adipocytes (fat cells). This is body fat.
Adipocytes: individual cells that store fats/lipids
Lipids: the most general term forinsoluble and polar biological fat molecules. The lipid class of molecules includes mono-, di- and triglycerols, cholesterols, and phospholipids
Triglycerides: a lipid molecule made up of glycerol (that acts as a backbone) joined to three fatty acid molecules
Fatty acids: a molecule composed of a chain of carbon atoms bonded to one another with a carboxylic acid at one end
To be specific, our diet includes many sources of lipids.
Lipids are digested and travel in the blood as triglycerides and fatty acids before being used as a fuel, or stored by adipocytes in adipose tissue. Dietary lipids undergo many tightly regulated metabolic steps before storage in adipose tissue. Dietary fat does not equal stored body fat.
Triglycerides are the most important source of energy in a ketogenic diet. They account for > 70% of dietary calories. For those following a ketogenic diet, it’s helpful to understand how the lipid source in the diet is processed in the body.
Fatty acids can be saturated (no double bonds between carbons), or unsaturated (one or more double bonds between carbons).
Saturated fats are relatively stable and tend to be solid at room temperature (i.e. lard, butter, coconut oil). Historical guidelines recommended limited the intake of dietary saturated fats because fat consumption was thought to be associated with heart disease and high blood pressure. However, emerging research has shown saturated fat can have beneficial effects on blood biomarkers (i.e. increase healthy HDL cholesterol levels).17
Unsaturated fatty acids can be further divided into monounsaturated fats (only one double bond between carbons) and polyunsaturated fats (multiple double bonds between carbons). The number of double bonds is important as it determines how the fatty acid behaves both inside and outside of the body.
They tend to be liquid at room temperature (i.e. vegetable-based fats such as olive oil). Unsaturated fats are thought of as healthier than saturated fats (also known as “healthy fats”). Increased consumption of mono- and polyunsaturated fats have been linked to improved blood biomarkers (i.e. lower blood triglycerides).18 Eating enough unsaturated fats is important when following a ketogenic diet.
Increased fat consumption is not associated with cardiovascular disease.19
Eating a moderate amount of saturated fat is unlikely to be as harmful as previously believed, and saturated fat consumption as part of a ketogenic diet is unlikely to increase the risk of cardiovascular disease.
Trans-fats are produced artificially when hydrogen is added to unsaturated fatty acids in order to solidify it and make it last longer. Because of associations with poor health outcomes, these artificial fats had their generally regarded as safe (GRAS) status removed in 2015 by the FDA. 20 Avoid high levels of trans-fat consumption by eating a diet based around whole foods.
Essential fatty acids are important to include in the diet because the body cannot naturally produce them. This group includes poly-unsaturated omega 3, omega 6, and omega 9 fatty acids.
It’s believed the anti-inflammatory effects of essential fatty acids may have broad benefits for health and performance. Oily fish, such as sardines and mackerel, and seeds (i.e. flax) are good dietary sources of essential fatty acids. If you don't get enough of these in your diet you can take a supplement that includes fish oil,
such as Kado, from HVMN.
The number of carbons in the fatty acid chain also has an important effect on its metabolism. The carbon chain of fatty acids can be up to 28 carbons atoms long. If there are > 13 carbons in the fatty acid, it is called a long-chain fatty acid, between 8-12 is a medium-chain fatty acid, and under 5 carbons is a short-chain fatty acid.
The body metabolizes fats differently according to chain length. Long-chain fatty acids are absorbed and go from the gut into the lymphatic drainage system and from there are released directly into the blood.
By comparison, medium- and short-chain fatty acids do not go into the lymphatic system. They travel in the blood from the gut directly to the liver.21 If a large amount of these short- and medium-chain fats are delivered to the liver at once, this can trigger the liver to convert them into ketones, even without dietary carbohydrate restriction.
Medium-chain fatty acids are highly ketogenic. They can be found in natural sources such as coconut oil or in an artificially purified form. However, for many people, consuming a high amount of medium-chain fatty acids can cause an upset stomach. This limits their use to raise ketones artificially.
When integrating these concepts into a ketogenic diet: target the majority of dietary calories as fat. Aim to include a variety of fats from different animal and plant sources (i.e. red meat, poultry, fish, dairy, olive oil, coconut oil, nuts, and avocados).
Micronutrients on a Keto Diet
Conversely to macronutrients, micronutrients must be obtained in the diet in small quantities, but are essential to health. Vitamins and minerals are examples of micronutrients.
When following a ketogenic diet, it is important to be mindful of micronutrient intake because:
Reducing carbohydrate intake can lower consumption of micronutrient-rich foods (i.e. fruits and vegetables)
In the initial 28 days of following a ketogenic diet, the balance of some micronutrients (such as sodium, potassium, magnesium, and calcium) can become disturbed due to an increase in their excretion.22 The body resolves this issue naturally after adapting to the diet
Sodium is the principal cation in extracellular fluid. Its functions are related to blood volume maintenance, water balance, and cell membrane potential. Sodium is also essential for acid-base balance and nerve conduction.
The level of sodium can fall at the start of a ketogenic diet.
Adding extra sodium to meals (like adding salt or consuming bouillon/ bone broth) can reduce the chances of feeling the common side effects associated with low sodium (like cramps).
Potassium is the principal cation in the intracellular fluid. Its primary functions are related to maintaining cell membrane potential and electrical activity in cells such as neurons and cardiomyocytes. As with sodium, levels of potassium fall at the initiation of a ketogenic diet due to increased excretion. When starting a ketogenic diet, include sources of potassium like nuts, dark green vegetables, and avocados.
Magnesium is an essential element in biological systems, especially for nerve, muscle, and immune function. Levels of magnesium also fall at the initiation of a ketogenic diet due to increased excretion. When starting a ketogenic diet, include sources of magnesium like oily fish, dark green vegetables, and seeds.
Calcium has a role in muscle contraction and is important for cardiovascular and bone health. Calcium deficiency is less common during a ketogenic diet, as staples of the diet such as fish, cheese, and leafy greens are rich sources of the mineral.
Considerations When Starting a Keto Diet
As with any new diet or way of life, it's important to look at the lifestyle change from all angles.
Who Should Avoid a Keto Diet?
Based on certain risk factors, following a ketogenic diet may not be suggested for people with the following medical considerations:
Impaired liver function
Impaired fat digestion (gallbladder disease, gastric bypass, pancreatitis)
Genetic defects in metabolism (CPTI/II deficiency, beta-oxidation defects, fatty acyl dehydrogenase deficiency).
Potential Side Effects