Want to lose weight on a ketogenic diet? Don’t worry! Learn these first

Author: Xue Qingxin, registered dietitian

Reviewer: Zhang Yu, researcher at Chinese Center for Disease Control and Prevention

Summer is the "peak season" for weight loss. Getting rid of obesity can not only improve your spirit, but also reduce the burden on your body. In recent years, the "ketogenic diet" has been favored by many weight loss partners. So, what is the ketogenic diet for weight loss? Can it really help you lose weight? In this article, we will talk about the ketogenic diet.

1. What is the ketogenic diet?

The ketogenic diet was first proposed by an American physician in 1921. From the name, we can generally know that it is a dietary pattern that allows the body to produce ketone bodies. It is a high-fat, low-carbohydrate diet supplemented with appropriate amounts of protein and other nutrients. The "ketone bodies" are incomplete oxidation products of fatty acids in the liver, including acetoacetic acid, β-hydroxybutyric acid and acetone. After production, they must be transported to extrahepatic tissues for oxidation through the blood. During strenuous exercise, the body produces more ketone bodies (from the "Approved and Published Terminology Database").

This dietary pattern was originally designed to treat epilepsy, and is currently used to treat a variety of diseases including obesity, type 2 diabetes, tumors, autism, Parkinson's disease, Alzheimer's disease, polycystic ovary syndrome, and brain and spinal cord injury.

In the ketogenic diet pattern, the energy supply ratio of the three major nutrients is: carbohydrates ≤10%, protein 20%, and fat 70%; while in our normal diet pattern, the energy supply ratio of the three major nutrients is carbohydrates 50%~65%, protein 10%~15%, and fat 20%~30%.

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Under normal circumstances, when we consume enough carbohydrates and fats, energy consumption mainly comes from glucose decomposed from carbohydrates; fat can also be completely burned to produce carbon dioxide and water. In a ketogenic diet, carbohydrate intake is too low and fat is high, so glucose is insufficient and the body can only burn fat for energy; and because there are too few carbohydrates, fat cannot be completely burned, which in turn produces ketone bodies, which is the so-called "ketogenic reaction."

2. Adverse reactions that need to be watched out for on the ketogenic diet

From the above, we can see that the ketogenic diet converts the body's original glucose energy supply into ketone body energy supply. At the beginning, the body is not adapted and will have some adverse reactions. Long-term adherence may also have adverse reactions.

(1) Hypoglycemia reactions: dizziness, palpitations, weakness, cold sweats, etc. These symptoms may gradually improve after one week.

(2) Drowsiness and lack of energy: This symptom usually disappears within 1 to 2 weeks.

(3) Skin itching and rashes: Some people are allergic to ketone bodies and may experience allergic reactions such as skin itching or rashes.

(4) Constipation: Eating less food than normal, and significantly reducing the intake of staple foods and fruits and vegetables, will result in too little food residue and insufficient dietary fiber intake, which is not enough to stimulate the intestines to produce the urge to defecate, making constipation more likely over time.

(5) Malnutrition: Ketone bodies have a diuretic effect, and the types and amounts of food in the diet are significantly reduced, which can lead to vitamin and mineral deficiencies, mainly involving vitamin B, vitamin C, vitamin D, calcium, selenium and magnesium, which can increase the risk of malnutrition.

(6) Amenorrhea: Women are likely to experience menstrual irregularities and amenorrhea.

(7) Osteoporosis: Long-term ketogenic diet may lead to vitamin D and calcium deficiency, decreased bone density, and increased risk of osteoporosis.

(8) Increased risk of kidney stones: It has been reported that the incidence of kidney stones associated with the ketogenic diet is 3% to 7%, and the incidence of kidney stones in those who have been following the ketogenic diet for more than 6 years is as high as 25%.

(9) Cardiovascular disease: The ketogenic diet contains a high amount of fat. If a high amount of saturated fatty acids is consumed, it will lead to elevated blood lipids and affect cardiovascular health.

(10) Others: The latest research shows that long-term ketogenic diet will lead to increased levels of bad cholesterol in the body, doubling the risk of cardiovascular events such as angina pectoris, arterial embolism, heart attack, and stroke!

3. How to eat a ketogenic diet?

Although the ketogenic diet will produce the above adverse reactions, many people are still willing to try it in order to lose weight as soon as possible. Studies have shown that the ketogenic diet can effectively reduce body weight, reduce waist circumference, and improve patients' fasting insulin levels and insulin resistance. So, how should the ketogenic diet be eaten?

If you are between 18 and 65 years old and your body mass index (BMI) is ≥24 kg/m2, you can try a ketogenic diet under the guidance of a doctor or professional. The BMI algorithm is weight (kg)/height (m2).

According to the average female's daily calorie intake of 1,800 kcal, if a ketogenic diet is to be adopted, the amount of carbohydrates, protein and fat that needs to be consumed each day is 45 grams, 90 grams and 140 grams respectively. What does this mean? For details, please refer to the figure below.

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Pay attention to the following food intake requirements:

(1) Staple foods and fruits: They are the main sources of carbohydrates. If you eat a little more, your carbohydrate intake will easily exceed the standard. Therefore, you can only eat a little or no food at all (except avocados, which are low in carbohydrates, high in fat, and rich in monounsaturated fatty acids, so they are recommended).

(2) Vegetables: Only vegetables with low carbohydrate content can be selected, such as winter melon, Chinese cabbage, baby cabbage, rapeseed, oats, cabbage, kale, spinach, broccoli, eggplant, tomato, bell pepper, cucumber, zucchini, soybean sprouts, mung bean sprouts, etc. Vegetables with high carbohydrate content, such as lotus root and edamame, should not be selected.

(3) Milk: Milk contains lactose, which is a carbohydrate. The carbohydrate content of yogurt is also high, so you should drink less of both.

(4) High-fat foods: Eat more! But don’t choose foods with high saturated fatty acid content. It is recommended to choose foods rich in n-3 unsaturated fatty acids, such as salmon, mackerel, etc.

(5) Cooking oil: You can choose olive oil, linseed oil, or perilla seed oil. Avoid choosing oils high in saturated fatty acids, such as lard, coconut oil, and butter.

(6) Meat, beans, and eggs: These high-protein, low-carbohydrate foods can be eaten in moderation.

(7) Drink more water: Drink at least 2000 ml of boiled water every day.

(8) Take dietary nutritional supplements every day.

4.Who cannot follow the ketogenic diet?

The ketogenic diet is not suitable for everyone. The following people are not recommended to try it:

(1) Pregnant and lactating women.

(2) People with certain diseases: such as gout, hyperuricemia, kidney stones, pancreatitis, type 1 diabetes, severe gastroesophageal reflux, liver disease, high blood lipids, heart disease, etc.

Finally, I would like to remind you that even if you are not in the above range, do not try the ketogenic diet at will. If you want to try it, you need to understand your physical condition first and do it under the guidance of professionals. And do not stick to it for a long time. Generally, you need to re-evaluate your physical condition after about 2 weeks and then decide whether to continue.

References:

[1] Jiang Bo, Zou Dajin, Ma Xianghua, et al. Chinese expert consensus on ketogenic diet intervention for type 2 diabetes (2019 edition)[J]. Journal of Practical Clinical Medicine, 2019, 23(3): 1-6.

[2] Wang Hui, Ma Jingping. Research progress on ketogenic diet for the treatment of epilepsy[J]. Journal of Integrated Traditional Chinese and Western Medicine for Cardiovascular and Cerebrovascular Diseases, 2021, 19(22): 3923-3926.

[3]https://www.acc.org/About-ACC/Press-Releases/2023/03/05/15/07/Keto-Like-Diet-May-Be-Linked-to-Higher-Risk