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Learn what metabolic health is and why it is critical for healthy life and longevity.
Type 2 diabetes (T2DM) is a debilitating condition when the metabolism of carbohydrates, fats, and protein is disrupted. Diabetes greatly increases one's chances of heart and kidney disease, nerve damage, vision loss, chronic pain, autoimmune disorders, and even cancer. The disease can take years to develop, anywhere from 5-10 years. The symptoms are nonspecific and usually mild. Diabetes can come as a surprise. By the time of the diagnosis, up to 50% of the pancreatic function may be lost. According to the CDC, 1in 3 Americans have pre-diabetes and 81% of them don't know about it [1].
Diabetes is getting younger. More and more adolescents and young adults are diagnosed every year. It is a silent epidemic.
In 2021 the prescriptions for metformin, a first-line treatment drug for diabetes, has more than doubled since just a decade ago, exceeding 91 million doses.
Diabetes is characterized by elevated fasting blood glucose equal to or greater than 126 mg/dL, random blood glucose level of 200 mg/dL, symptoms of excessive thirst, hunger, and urination, as well as extreme fatigue, blurred vision, poor wound healing, and frequent infections. Individuals with Type 2 diabetes often struggle with excessive weight and obesity, but not always.
But what if your blood sugar levels are below the diabetic or even pre-diabetic range on your annual well-visit blood test, and your weight is normal, is it enough to consider yourself metabolically healthy?
The short answer is "No". Let's take a closer look.
What is Metabolism and Metabolic Health?
Metabolism is a sum of all biochemical reactions in the body that either consume or produce energy. Metabolic reactions transform food into energy, make building blocks to build and repair cells and DNA, support breathing and blood circulation, and eliminate waste. Metabolic processes are extremely complex and are powered by a myriad of nutrients and hormones like insulin, cortisol, estrogen, testosterone, thyroid, and others.
The term "metabolic health" is commonly associated with weight. But normal body weight is not the only determining factor of healthy metabolism. A large percentage of people in the US with normal weight are metabolically unhealthy. Only 12% of the American population meets all the criteria to be considered metabolically fit [2].
The criteria to be considered metabolically healthy [2] :
Waist circumference <102 cm for men, and <88cm for women
Glucose (fasting glucose <100 mg/dL and hemoglobin A1c <5.7%),
Blood pressure (systolic <120 and diastolic <80 mmHg),
Triglycerides (<150 mg/dL)
HDL (the "good" cholesterol) (≥40 mg/dL for men, ≥ 50 mg/dL for women)
Not taking any related medication.
These are the numbers we want to see on the lab test. But what do they tell us, and how they are related?
Visceral vs Subcutaneous fat. Apples vs. Pears.
Not all fat is created equal. You probably know this is true for dietary fats. But it also applies to the fat found in the human body. When it comes to metabolic health, how fat is distributed in the body is a more important factor than the total body weight or Body Mass Index (BMI) alone.
When fat is concentrated around the midsection, it gives the body an apple-like shape. When fat is located under the skin and on the hips and thighs, the body takes more on the appearance of a pear. The type of fat around the midsection is known as visceral fat because it surrounds the viscera, or soft internal organs like the liver, pancreas, and intestines. On the other hand, the fat under the skin is called subcutaneous. Metabolically, these are two very different types of fat. Visceral fat is a lot more dangerous because it is closely linked to metabolic imbalances and cardiovascular risks.
Men typically carry weight around the midsection, while women tend to accumulate more fat around the hips and thighs. In menopause, due to a drop in estrogen, a woman's body may start to change from a pear to more of an apple. Visceral fat in the right amount is necessary to protect and insulate the internal organs. However, excess visceral fat acts like an endocrine organ releasing pro-inflammatory chemicals called cytokines which disrupt metabolic hormones like insulin and adiponectin. Visceral fat affects the liver's ability to produce and regulate glucose. This can result in high blood sugar, insulin resistance, and eventually diabetes [3], [4]. Visceral fat is invisible to the eye but can be measured through waist circumference, waist-to-hip ratio, or with a BIA scale.
Insulin Resistance and Metabolic Syndrome.
When the blood sugar rises, insulin is released by the pancreas to send glucose inside the cells. When it comes to controlling blood sugar levels, insulin is a master hormone without a peer. Besides keeping blood sugar levels in the normal rangers, insulin stimulates the production of fatty acids from excess glucose and fructose and promotes the formation of triglycerides in the liver that get shipped as VLDL (very low-dense lipoproteins) to the fat tissue for storage.
When the blood sugar is consistently high, more insulin is required to maintain blood sugar levels within normal ranges. Over time stressed cells become resistant to insulin. As a result, muscle and fat cells cannot get the energy they need. Despite high blood sugar levels, the starving cells send an SOS signal to the brain causing excessive hunger and sugar cravings.
Insulin resistance and excess visceral fat affect another important hormone of metabolism, adiponectin. Adiponectin regulates body fat, increases insulin sensitivity, and reduces inflammation. It inhibits the liver's ability to make and store glucose as fat in the belly and promotes fat to be burned for energy. Adiponectin is made in the fat cells but is often found low in individuals with excess visceral fat.
Insulin resistance and non-alcoholic fatty liver disease (NFLD) .
Unlike muscle and fat cells, liver and kidney cells remain insulin sensitive. The liver starts making a lot of VLDL from the triglycerides that come from the excess glucose. This is when we see elevated serum triglycerides and VLDL on the lipid panel. Excess triglycerides are stored in the liver as fat, which can eventually cause non-alcoholic fatty liver disease (NFLD) and liver damage [5]. It is estimated that 47% of Americans have fatty liver [6].
Excess glucose is stored in the fat cells that become enlarged (hypertrophy). When these cells reach maximum capacity to accommodate the triglycerides, new fat cells are formed (hyperplasia). What is interesting, is that when the fat is lost, the number of fat cells does not decrease, they only become smaller in size.
Insulin Resistance and High Blood Pressure Connection.
High insulin makes kidneys retain salt and uric acid. This increases blood pressure and causes uric acid levels to remain high in the serum. Accumulation of uric acid crystals in the kidneys may result in kidney stones and kidney disease. High levels of uric acid are known to provoke gout, an inflammatory and painful condition when uric acid crystals accumulate in the joints.
Triglycerides to HDL Ratio.
Triglycerides/ HDL ratio is a good marker of insulin resistance.
A ratio of < 1.5 indicates good metabolic function and a low risk of heart disease.
A ratio greater than 2.6 indicates metabolic syndrome and an increased risk of cardiovascular disease. Ideally, I like to see triglycerides under 100 mg/dL.
Inflammation and Chronic Disease
Metabolic syndrome is a major source of chronic low-grade inflammation and immune activation in the body. Low-grade Inflammation is linked to many chronic conditions like heart disease, kidney and gall bladder disease, rheumatoid arthritis, autoimmune conditions, neurodegenerative diseases, and cancer.
Many research studies suggest that Alzheimer's disease is closely related to blood sugar dysregulation. The connection is so strong that some call Alzheimer's "diabetes of the brain, or "Type 3 Diabetes" [7].
Balancing Blood Sugar
Balanced blood sugar is the core foundation of good metabolic health. Avoiding blood sugar spikes and dips is key to maintaining this balance.
After we eat something sweet, we may feel a quick burst of energy, but after about an hour, we feel hungry again. It is because a lot of insulin has been released to send the glucose into the cells, and now when the levels of sugar in the blood are low, we may feel shaky, anxious, and unfocused. We reach for more sugary snacks and caffeine to "pick us up". It is a vicious cycle.
Many people are controlled by sugar, struggling with cravings and hunger for sweets and feeling jittery and exhausted throughout the day. An average American eats 126 pounds of sugar each year. That's almost 31 teaspoons of sugar per day!
Pure sugar is a fairly new addition to the human diet. It is estimated to be present in 75% of packaged foods [8]. It is hard to avoid sugar in our food culture today. Commercially produced foods and drinks are loaded with sugar. It is in everything from coffee lattes to breakfast cereals, soft drinks, juices, salad dressings, bread and crackers, pasta and BBQ sauce, frozen dinners, granola bars, low-fat sweetened yogurt, condiments, and the list goes on.
How to control sugar intake.
Try tracking your sugar intake for a few days. Read the labels of the foods you eat daily and add them at the end of the day. You may be surprised at how much sugar these foods contain. Just a few examples: one 12-ounce can of soda contains 8 teaspoons (32 grams) of added sugar. One cup of Fruit Loops contains 3.75 teaspoons of sugar.
Keep in mind that simple carbohydrates like white bread, pasta, cereals, white rice, crackers, pretzels, chips, and processed grain flours (even gluten-free) quickly turn into sugar molecules in the body. This is because the fiber has been mostly taken away and the fine particles in the flour get digested quickly, causing a spike in blood glucose. It is best to reduce or avoid foods made with ground flour and opt for whole grains and legumes instead.
A good rule of thumb is to not exceed 9 teaspoons (36 grams or 150 calories) of added sugar per day for men.
For women: 6 teaspoons (25 grams or 100 calories) per day.
Children: 3 teaspoons per day or 12 grams.
When it comes to diet, the best advice I give to all of my clients is to eat balanced meals throughout the day. A balanced meal includes ample amounts of protein, healthy fats, and fiber. Foods higher in protein and fat do not require nearly as much insulin as simple carbohydrates do, decreasing basal insulin over time and increasing cells' sensitivity to insulin. Fiber slows down the absorption of carbohydrates in small intestines and brings them into the large intestines, thus decreasing the insulin response.
Maintaining good metabolic health is critical if we want to keep our bodies healthy and strong and our minds sharp when we are in our 60s, 70s, 80s, and 90s and beyond.
It is never too late to start.
In Part 2 of this metabolic series, we will take a deeper dive into not-so-commonly known factors that can affect metabolism, sabotaging fat loss goals, especially for women.
Stay tuned!
Did you find this article helpful? I would love to hear from you.
Let me know in the comments below!
References:
CDC.gov https://www.cdc.gov/media/releases/2023/p1114-adult-diabetes.html
Araújo, J., Cai, J., & Stevens, J. (2018). Prevalence of Optimal Metabolic Health in American Adults: National Health and Nutrition Examination Survey 2009–2016. Metabolic Syndrome and Related Disorders. doi:10.1089/met.2018.0105 https://www.liebertpub.com/doi/10.1089/met.2018.0105
Neeland, I. J., Hughes, C., Ayers, C. R., Malloy, C. R., & Jin, E. S. (2017). Effects of visceral adiposity on glycerol pathways in gluconeogenesis. Metabolism, 67, 80–89. doi:10.1016/j.metabol.2016.11.008 ://doi.org/10.1016/j.metabol.2016.11.008
Goswami B, Reang T, Sarkar S, Sengupta S, Bhattacharjee B. Role of body visceral fat in hypertension and dyslipidemia among the diabetic and nondiabetic ethnic population of Tripura-A comparative study. J Family Med Prim Care. 2020;9(6):2885-2890. Published 2020 Jun 30. doi:10.4103/jfmpc.jfmpc_187_20
Alves-Bezerra M, Cohen DE. Triglyceride Metabolism in the Liver. Compr Physiol. 2017;8(1):1-8. Published 2017 Dec 12. doi:10.1002/cphy.c170012
Teng ML, Ng CH, Huang DQ, et al. Global incidence and prevalence of nonalcoholic fatty liver disease. Clin Mol Hepatol. 2023;29(Suppl):S32-S42. doi:10.3350/cmh.2022.0365
Nguyen TT, Ta QTH, Nguyen TKO, Nguyen TTD, Giau VV. Type 3 Diabetes and Its Role Implications in Alzheimer's Disease. Int J Mol Sci. 2020;21(9):3165. Published 2020 Apr 30. doi:10.3390/ijms21093165White JR Jr.
Sugar. Clin Diabetes. 2018;36(1):74-76. doi:10.2337/cd17-0084
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