When trying to lose weight, a common first reaction is to immediately reduce your carbohydrate intake or even stop eating it. Do carbohydrates really cause obesity and are not good for your health? It must be based on its structure and its impact on blood sugar fluctuations. Carbohydrates are one of the important components of a healthy diet. 45 to 60% of the total calories in a balanced diet come from carbohydrates. The “staple foods” of most ethnic groups are carbohydrate foods, such as rice, bread, potatoes and pasta. However, not all carbohydrates are the same, and they are simply divided into 2 major categories: “simple carbohydrates” and “complex carbohydrates.”
Eating too many “simple carbohydrates” increases the risk of chronic diseases
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The human body can only directly absorb “glucose” to form what is called “blood sugar”. Therefore, disaccharides (sucrose, lactose) and polysaccharides (starch) must be decomposed and converted into glucose before they can be quickly absorbed and utilized. The simpler the structure of carbohydrates, the easier it is for the body to absorb, and the faster blood sugar rises. Food sources of simple carbohydrates:
1. Sugar:Sugary drinks, candy, sucrose, honey, fructose, high fructose corn syrup (HFCS, a sweetener made from corn starch, commonly added to sugary drinks and various processed foods) and agave syrup, etc.
2. Refined grains:White flour, white bread, white rice, pastries, pasta, breakfast cereals, etc.
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During the milling process of grains, the bran and germ as well as many nutrients are removed, leaving refined grains with almost no fiber, vitamins or minerals. What is left is quickly digestible starch and a very small amount of protein, which is Considered as “empty calorie food”. Empty calorie foods refer to foods that contain calories mainly from sugar, oil, fat or alcohol, but have little or even no other nutritional value, such as cakes, cookies, donuts, muffins, soda, etc.
Therefore, consuming too many simple carbohydrates, especially high-fructose corn syrup, increases the risk of chronic diseases such as obesity, cardiovascular disease and type 2 diabetes, colon cancer, and various digestive problems.
Consuming “complex carbohydrates” does not entirely lead to obesity
Carbohydrates with a complex structure are like many beads tightly connected together. It takes a long time to convert them into glucose (single bead) in the digestive system, and the rate of blood sugar rise is relatively slow. Therefore, it is not exclusively foods containing complex carbohydrates that cause obesity or health problems, but rather refined foods containing simple carbohydrates that are likely to cause obesity.
The so-called whole grain must contain the three parts of the grain prototype: bran, germ and endosperm.
Grain cross-section: from outside to inside are bran, aleurone layer, endosperm, and germ.
The bran and germ are the most nutritious parts of whole grains and contain many nutrients such as dietary fiber, B vitamins, iron, magnesium, phosphorus, manganese and selenium. During the milling process of whole grains, almost all of the fiber, vitamins and minerals are removed. In order to meet nutritional requirements, some products will add synthetic vitamins to make up for the nutrients lost during processing, which is labeled as “fortified” on the food packaging. However, whether synthetic vitamins are as effective as natural vitamins has long been debated. It is undeniable that nutrients already present in natural foods are always the best sources.
Therefore, the complexity of carbohydrates in a healthy diet is extremely important for the ups and downs of blood sugar. Among them, the relationship between the intake of whole grains and the risk of chronic diseases cannot be ignored. Analysis of a series of research reports shows that increasing the intake of whole grains can reduce the risk of cardiovascular disease, type 2 diabetes, metabolic syndrome and multiple cancers. The “glycemic index” is an indicator tool for choosing healthy carbohydrates.
What is “glycemic index”?
The glycemic index is a comparison of the rise in blood sugar 2 hours after eating a food containing 50 grams of carbohydrates. Set the impact of sugar and white toast on blood sugar as 100, and then compare the speed of blood sugar rise with other foods. Carbohydrate foods are then classified into “high glycemic” (high or equal to 70), “medium glycemic” (56 to 69) and “low glycemic” (low or equal to 55) indexes. In other words, only carbohydrate-based foods have a so-called glycemic index, while fat and protein foods do not have a glycemic index.
How to moderate the impact of carbohydrates on blood sugar fluctuations?
Simple carbohydrate foods, such as sugar, white flour and white rice, are all high-glycemic foods, which means that after ingestion, blood sugar will rise significantly in a short period of time. In order to maintain blood sugar within the normal range, the body’s homeostasis mechanism ) will automatically secrete “insulin” to convert excess blood sugar into glycogen or fat.
The daily diet should reduce the intake of high-glycemic foods and increase the intake of low-glycemic foods. When choosing foods with high starch content, such as potatoes and sweet potatoes, the skins of these roots are rich in nutrients and fiber. Try brushing the skins of potatoes or sweet potatoes clean and eating them with the skins on. Using brown rice or whole grains instead of white rice, or adding soybeans, black beans, red beans, and barley to white rice can not only increase the dietary fiber content, but also increase the nutritional value.
If you eat foods with a high glycemic index, such as white noodles, bread, and white rice, be sure to include low-glycemic vegetables or legumes in the same meal to moderate the impact of the overall diet on blood sugar and make it gentle without a large rise or fall. .
What is a “low-carb diet”?
In a balanced diet, the calories from carbohydrates account for 45 to 60% of the total calories, which is equivalent to 225 to 300 grams. A diet with a carbohydrate intake of less than 130 grams is considered a “low-carbohydrate diet”, and the carbohydrate intake in a day must not be less than 50 grams. It is correct to follow a “low simple” carbohydrate diet, but it is necessary to consume enough nutrient-dense, whole, unprocessed foods, which can reduce blood pressure and triglyceride concentrations and benefit cardiovascular health. Long-term carbohydrate restriction may lead to deficiencies in certain vitamins or minerals and digestive problems.
A bowl of white rice contains about 50 grams of carbohydrates, a piece of white toast contains about 20 grams of carbohydrates, and a medium orange contains about 10 to 13 grams of carbohydrates.
Most of the weight lost on the “ketogenic diet” is water weight, which is easily regained!
The ketogenic diet is a high-fat, high-protein, very low-carbohydrate diet that forces physiological metabolism to burn body fat. In traditional medicine, the ketogenic diet is mainly used to treat uncontrollable epilepsy in children, but it is now being abused for weight loss. A general ketogenic diet recommends that 70 to 80% of total daily calories come from fat, 5 to 10% from carbohydrates, and 10 to 20% from protein. A balanced diet requires 20 to 35% of total calories from fat, 45 to 65% from carbohydrates, and the remaining 10 to 35% from protein.
In other words, the ketogenic diet usually reduces the total carbohydrate intake to less than 50 grams per day, and even as low as 20 grams per day in the first 2 weeks. The ketogenic diet may be able to lose weight quickly, but it is an extremely unhealthy and dangerous extreme method. Most of the weight lost is water, and it is easy to regain it. This diet is high in animal fats and proteins, which can increase the risk of cardiovascular disease or certain cancers in the long term.
What are the physiological effects of extreme carbohydrate restriction on a ketogenic diet?
If the carbohydrate intake in a day is less than 50 to 80 grams, the physiological metabolism in the body will change, leading to the following symptoms:
1. Fatigue or headache: When the body does not have an appropriate amount of blood sugar as an energy source, it is forced to use ketones and fat, and flu-like symptoms may occur in the early stages of the ketogenic diet.
2. Kidney load: Ingesting a large amount of animal protein on a ketogenic diet makes urine acidic, increasing the risk of kidney stones. At the same time, it may worsen existing chronic kidney disease.
3. Constipation: While limiting carbohydrate intake, it will also limit the intake of fruits and vegetables. Therefore, the intake of fiber is low, which can easily cause constipation and have a negative impact on intestinal health.
4. Nutrient deficiencies: The content of the ketogenic diet does not provide enough vitamins and minerals (including potassium and magnesium), which will lead to deficiencies of certain nutrients over time.
5. Chronic diseases: Although research results are mixed, there is still evidence that a low-carbohydrate diet based on animal foods may cause cardiovascular disease and even increase mortality from some cancers.
6. Hypoglycemia: Although low-carbohydrate diets have been proven to improve blood sugar control in patients with diabetes, they may also be at risk of hypoglycemia, especially for those with type 1 diabetes.
7. Depressed mood: Insulin is required for blood sugar to enter cells, and insulin is also required for tryptophan to enter brain cells. Therefore, extreme restriction of carbohydrate intake will cause depression, depression and even depression. (Tryptophan affects the concentration of serotonin, a neurotransmitter with complex biological functions, including mood, cognition, reward, learning, memory, as well as vomiting and vasoconstriction.)
8. Bad breath: Bad breath occurs due to the production of ketone bodies. Acetone is a ketone excreted from the body through urine and breathing.
“Diabetes” is caused by eating too many carbohydrates?
The main cause of diabetes is insufficient insulin function and the inability to effectively regulate blood sugar concentrations within the normal range. On the contrary, people with normal insulin function will not experience blood sugar abnormalities no matter what type or amount of carbohydrates they consume. Therefore, the focus of the diabetes diet is to avoid foods that cause excessive fluctuations in blood sugar, that is, foods with a high glycemic index, and try to choose foods with a low or medium glycemic index.
A review published in Nutrition magazine in September 2018 found that those who consumed 60 to 90 grams of whole grains per day (about 2 or 3 servings) were less likely to develop type 2 diabetes than those who never or rarely ate whole grains. The risk can be reduced by 21 to 32%, because whole grains have a lower glycemic index, unlike simple carbohydrate foods or foods that can quickly affect blood sugar concentrations. In addition to food adjustments, exercise is one of the important keys to improving blood sugar.
The harm of hypoglycemia cannot be ignored
Although there is widespread concern about the harm to health caused by high blood sugar (≥125 mg/100c.c), “hypoglycemia” (insufficient glucose concentration in the blood) is more dangerous than high blood sugar and may be life-threatening. Hypoglycemia refers to a blood sugar concentration lower than the normal range (120-80 mg/100c.c). This usually occurs in diabetic patients because the pancreas of diabetic patients has dysfunction in regulating hormone secretion and cannot function as well as non-diabetic patients. Blood sugar can be adjusted in a timely manner to maintain normal concentration.
For many patients with diabetes, a blood sugar concentration lower than 70 mg/100c.c is called hypoglycemia. The brain needs blood sugar to function. When hypoglycemia occurs, the first organ to be damaged is the brain. Severe or prolonged hypoglycemia can lead to seizures and severe brain damage, or even coma or death, depending on its severity or duration. .
[This article is the opinion of the author and does not represent the position of this media]
Reviewing Editor: Lin Yuting
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▶Hu, Y., Ding, M., Sampson, L., Willett, WC, Manson, JE, Wang, M., Rosner, B., Hu, FB, & Sun, Q. (2020). Intake of whole Grain foods and risk of type 2 diabetes: results from three prospective cohort studies. BMJ (Clinical research ed.), 370, m2206.
▶Vega-Lopez, S., Venn, B J., & Slavin, JL (2018) Relevance of the glycemic index and glycemic load for body weight, diabetes, and cardiovascular disease. Nutrients, 10(10), 1361.