Understanding Incomplete Proteins And Keto: A Quick Guide

The human body needs protein to form muscle, transport nutrients, and build and repair tissue. Protein is made up of amino acids, which are organic compounds. There are 20 different amino acids, 11 of which are produced by the body, while the remaining nine are obtained through food. A complete protein contains all nine essential amino acids, while an incomplete protein contains some, but not all, of these acids. Plant-based sources of protein are often deemed inferior to animal-based ones as they are considered to be incomplete proteins. However, this is considered a myth by some experts. The ketogenic, or keto, diet is a low-carb, high-fat diet that aims to force the body to burn fat for energy instead of carbohydrates.

Incomplete proteins are low in one or more of the essential amino acids that the body needs to build cells

Proteins are made up of building blocks called amino acids. There are hundreds of amino acids in nature, but only 20 are needed to make all the proteins found in the human body. These 20 amino acids can be further split into three main categories: essential, non-essential, and conditionally essential amino acids.

Essential amino acids are those that the body cannot produce and must be obtained from food. There are nine essential amino acids: histidine, valine, tryptophan, methionine, leucine, isoleucine, lysine, phenylalanine, and threonine.

Non-essential amino acids are those that the body can typically make from the nine essential amino acids. There are 11 non-essential amino acids.

Conditionally essential amino acids are typically considered non-essential but become essential during certain periods of life or under specific conditions, such as adolescence, pregnancy, trauma, or illness.

Foods that contain all nine essential amino acids are generally considered sources of "complete" protein. These include animal-based sources like meat, fish, eggs, and dairy, as well as plant-based sources like soy, quinoa, amaranth, buckwheat, and nutritional yeast, along with hemp and chia seeds.

Incomplete proteins are those that do not contain all nine essential amino acids or contain low levels of one or more of these amino acids. Most plant-based foods are considered incomplete proteins, including nuts, seeds, beans, legumes, whole grains, tofu, rice, and vegetables.

The concern with incomplete proteins is that following a diet with insufficient variety could lead to a deficiency in one or more essential amino acids. However, this concern may be considered more of a myth, especially for those following a vegetarian or vegan diet.

By combining different incomplete proteins, it is possible to obtain all the essential amino acids. This is known as complementary protein pairing. For example, legumes tend to be low in methionine and cysteine, while grains, nuts, and seeds tend to be low in lysine. Therefore, by consuming a combination of these food groups, an individual can obtain all the essential amino acids.

Additionally, the body can store essential amino acids, providing further flexibility. If an incomplete protein is consumed without a complementary protein, the body can supplement the missing amino acid from its stores.

In conclusion, while incomplete proteins are low in one or more essential amino acids, careful dietary planning can ensure that individuals still obtain all the essential amino acids necessary for building cells and maintaining overall health.

Plant-based sources of protein are often deemed inferior to animal-based ones

Plant-Based Proteins: Are They Really Inferior?

The "Complete" vs "Incomplete" Protein Debate

The terms "complete" and "incomplete" proteins refer to the amount of essential amino acids they contain. Essential amino acids are those that our body cannot produce and must be obtained from our diet. While animal-based proteins typically contain all nine essential amino acids in high levels, plant-based proteins usually have lower amounts of one or two of these amino acids.

However, this does not mean that plant-based proteins are inferior. In fact, there are several plant-based sources, such as soy, quinoa, amaranth, buckwheat, and nutritional yeast, as well as hemp and chia seeds, that offer good amounts of all nine essential amino acids and are considered "complete" sources of plant protein.

The Digestibility and Absorption of Plant-Based Proteins

One reason why plant-based proteins are sometimes considered inferior is because they are slightly more difficult for our bodies to absorb compared to animal-based proteins. This is mainly due to the different structures of plant and animal proteins, with plant proteins having a higher content of β-sheet conformation, which makes them more resistant to breakdown in the gastrointestinal tract. Additionally, plant-based sources often contain compounds like phytic acid and protease inhibitors, which can further decrease protein digestibility.

However, this difference in digestibility is minimal and can be improved through various processing techniques, such as heat treatment and enzymatic hydrolysis.

The Bottom Line

While it is true that animal-based proteins typically contain higher levels of essential amino acids, this does not mean that plant-based proteins are inferior. In fact, with a well-planned plant-based diet that includes a variety of protein sources, individuals can obtain all the essential amino acids they need. Additionally, plant-based proteins offer several health and environmental benefits that make them a valuable part of our diet.

Incomplete proteins can be combined to make a complete protein, e.g. grains and legumes

Incomplete Proteins Can Be Combined to Make a Complete Protein

Complete proteins contain all nine essential amino acids that the body cannot produce on its own. Incomplete proteins, on the other hand, contain some but not all of these essential amino acids and in varying amounts. Animal-based foods are typically considered complete proteins, while most plant-based foods are regarded as incomplete proteins. However, this is not always the case, as some plant foods like soy, quinoa, and buckwheat are complete proteins.

Combining incomplete proteins

You don't need to eat complete proteins at every meal to meet your protein requirements. The goal is to get a balance of essential amino acids throughout the day. This can be achieved by combining certain plant-based proteins, such as whole grains, nuts, and legumes, to provide your body with all the essential amino acids it needs to make a complete protein. For example, pairing legumes with whole grains like rice and beans, or lentils and barley, will give you a complete protein. Similarly, combining legumes with nuts and seeds will also result in a complete protein.

The general recommendation for healthy adults is to consume at least 0.36 grams of protein per pound of body weight each day. However, this may vary depending on your activity level and general health. It's important to space out your protein intake throughout the day as our bodies can only absorb a limited amount of protein per sitting.

The keto diet is a low-carb, high-fat diet

On a keto diet, your body enters a state of nutritional ketosis, where it burns fat for fuel instead of carbohydrates. This is achieved by limiting carbs and increasing fat intake, while keeping protein intake moderate. A keto diet usually consists of 5–10% carbs, 15–30% protein, and at least 70–80% fat.

The keto diet has therapeutic benefits, such as helping to treat epilepsy and potentially impairing the growth of certain types of cancer. It can also be used to lose weight, as it may reduce appetite and promote fat loss.

However, the keto diet is very restrictive and may be difficult to stick to long-term. It can also cause some unwanted side effects, such as constipation and the "keto flu", which includes symptoms like headaches, fatigue, and irritability.

Before starting any diet, it is important to consult a healthcare professional. They can help you decide if the keto diet is right for you, taking into account your individual health status, lifestyle, and nutrition habits.

The keto diet is associated with several health risks

The keto diet is high in saturated fat, which is linked to an increased risk of heart disease. It can also lead to:

• Nutrient deficiencies, as it restricts the intake of fruits, vegetables, and grains.
• Liver problems, as the liver has to metabolize a large amount of fat.
• Kidney problems, as the kidneys help metabolize protein.
• Constipation, as it is low in fibrous foods.
• Fuzzy thinking and mood swings, as the brain functions best with glucose from carbohydrates as its energy source.

In addition, the keto diet can cause digestive issues, kidney stones, muscle loss, and cognitive decline. It may also increase the risk of developing heart disease due to its high saturated fat content and lack of fiber.

Furthermore, staying on the keto diet long-term may have negative effects, including risks of low protein in the blood, extra fat in the liver, and micronutrient deficiencies. It is important to consult a doctor and a registered dietitian before attempting this diet.

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