The ultimate guide to type 2 diabetes

The ultimate guide to type 2 diabetes
Type 2 diabetes is a lifelong disease that can cause numerous complications. We dive into its causes and management to help you gain back control of your health.
Written by Orchid Team
Medically reviewed by Dr. Lila Chertman
  • Dr. Lila Chertman, MD, is board certified in endocrinology and internal medicine. She graduated from the University of Miami Miller School of Medicine, completed her residency at Mt. Sinai Medical Center and her fellowship at the University of Miami. She works in private practice in Miami.

What is type 2 diabetes?

Type 2 diabetes is a disease involving high blood sugar levels, a relative deficiency of insulin, and high levels of insulin resistance. It is a common disease, and the most common form of diabetes, accounting for as many as 90% of cases worldwide

On a basic level, type 2 diabetes occurs when the amount of insulin that your body produces is no longer enough to keep blood sugar levels normal.  This is usually the result of “insulin resistance”—when the target tissue of insulin responds less well. Insulin is the primary way that glucose (sugar) is directed into muscle and other tissues, so when someone has insulin resistance the target tissues fail to take in insulin from the blood, and hence, their blood sugar rises (“hyperglycemia”). In response, their pancreas makes more insulin, in an effort  to keep blood sugar levels relatively normal. Eventually, the ability of the pancreas to make enough insulin to overcome this resistance is exceeded, and blood sugar rises. In type 2 diabetics, the liver also releases too much sugar into the blood, causing further hyperglycemia. Over time, type 2 diabetics tend to become worse at making insulin, and develop correspondingly higher blood sugar levels. 

What are some risk factors for type 2 diabetes?

  • age
  • genetics
  • obesity
  • inactivity

At what age is type 2 diabetes typically diagnosed?

Older adults have much higher rates of type 2 diabetes. This is partly driven by increasing BMI with age, but there are strong age effects as well. About 10% of adults aged 70-79, with BMI between 26-30 (overweight, non-obese) have type 2 diabetes, compared to about 1% for adults aged 30-39, at the same BMI.

How does genetics impact my type 2 diabetes risk?

The heritability of the disease was estimated to be between 61-78% in a large twin study. Recent studies on Type 2 diabetes are implicating genes involved in beta cell (insulin-producing cells) survival, insulin receptor function, fat cell differentiation and more. 

How does obesity or my lifestyle impact my type 2 diabetes risk?

Obesity increases the risk of type 2 diabetes by causing insulin resistance and possibly by inflammation and other mechanisms. Inactivity, in addition to contributing to higher BMI, may also independently increase the risk of type 2 diabetes. Increased physical activity even in individuals who are already diabetic, can lead to improvements in insulin sensitivity and improvement in blood glucose levels.

What are some symptoms of type 2 diabetes?

Type 2 diabetes is often asymptomatic early on, but can cause severe complications over time, such as blindness, kidney failure, heart disease, and neuropathic pain. 

A useful measure of how well someone’s blood sugar is controlled is their hemoglobin A1C. The higher an A1C, the more likely they are to get complications from diabetes. Treatment for diabetes depends on several patient factors but mostly centers on safely reducing blood sugar levels and otherwise reducing risk for diabetic complications.

Figure 1: DiaThrive diagram of A1C

Is there anything I can do to reduce my risk of type 2 diabetes?

Broadly speaking, there are lifestyle changes, medication, and in some cases, surgery, which can all have varying effects on diabetes. Many of the interventions listed below are also treatments for type 2 diabetes.

What lifestyle changes can I make to reduce my risk of type 2 diabetes or treat it?

Many of the lifestyle recommendations for treating type 2 diabetes are similar to those for obesity. This is because losing more weight with a healthy but low-calorie diet generally improves diabetes control and may prevent development of diabetes in those at risk. 

Unfortunately, while strictly limiting calories reliably produces weight loss, only a fraction of people who try to lose weight succeed in sticking to an effective diet in the long-run. If you can stick with a diet, you’ve got a great shot at losing weight, which can improve insulin resistance substantially.

If you’re like most people, long-term weight loss will be difficult, since your body will tend to “defend” your previous weight: appetite will increase as you lose weight. A more in-depth explanation of these changes is found here.

For these reasons, while reducing calories and exercising more is excellent advice, most individuals with diabetes will not normalize their weight or their blood sugar, through lifestyle changes alone.

What medications can I take to reduce my risk of type 2 diabetes or treat it?

Though some complications from diabetes are not prevented with better blood glucose control, many are. For that reason, treatment of type 2 diabetes is designed to normalize blood sugar levels, while avoiding the risks of hypoglycemia (low blood sugar). Since diabetes also raises the risk of kidney disease and heart disease, better control of other risk factors in selected patients, such as high blood pressure and high cholesterol, is prioritized as well

There are multiple classes of medications for type 2 diabetes. In most cases, metformin is the initial medical treatment. Over time, if a patient’s blood sugar continues to rise, other medications are added or substituted. These range from drugs that decrease insulin resistance, increase insulin production, reduce liver glucose output, or some combination thereof. A full explanation of different drug classes and their indications can be found here

Until recently, there had been few effective and safe long-term medications for weight loss. Some apparent successes had later been withdrawn because of safety concerns, such as rimonabant and fenfluramine. However, a recent class of drugs that more directly target appetite, the GLP-1 agonists, are both safe and effective. Liraglutide and semaglutide, although expensive, are approved for use in obese adults and obese adults with at least 1 weight-related condition (such as diabetes), respectively.

What surgery can reduce my risk of type 2 diabetes or treat it?

There are surgical treatments for obesity (bariatric surgery) that are highly effective for type 2 diabetics that are obese. In those patients, surgery is likely more effective than drug therapy, though the surgery comes with potential short-term (acute surgical complications) and long-term (vitamin deficiencies) risks. 

In general, surgical treatment of obesity is offered for patients with a BMI > 35 and Type 2 Diabetes. Because it is a major surgery, patient selection is important, and doctors are cautious about performing the surgery in very sick patients. However, for those who qualify, it produces very impressive weight loss and health benefits. In some cases, likely because of the dramatic weight loss, it can reverse Type 2 diabetes, and is associated with a longer lifespan.

Is there anything I can do to reduce my child’s genetic risk?

As explained in the type 2 diabetes whitepaper, genetics plays an important role in determining the risk of diabetes. Using Orchid’s embryo scoring, you can prioritize the embryo with the lowest genetic risk and potentially reduce their risk of diabetes.  

How is type 2 diabetes diagnosed?

Diabetes is diagnosed through any one of the following:

  1. Blood glucose levels above 126 mg/dL after 8 hours or more of fasting
  2. A1C ≥6.5%
  3. In a patient with symptoms of hyperglycemia, a random plasma glucose ≥200 mg/dL 


  1. Type 2 diabetes is a chronic condition with large effects on your health: it raises the risk of heart attacks, strokes, kidney disease, vascular disease, erectile dysfunction, neuropathic pain, and more.
  2. There are medical, surgical, and lifestyle interventions that can effectively treat diabetes, but diabetes tends to worsen over time.
  3. Diet and exercise, if strictly adhered to, can cause substantial weight loss, which can improve diabetes, but long-term weight loss success without medication or surgery is uncommon. In addition, in diabetics who have lost all ability to make their own insulin, weight loss alone is insufficient to control diabetes.

Where can I learn more?

  1. Nutrition in Prediabetes and Type 2 Diabetes, with Dr. Nicola Guess.
  2. Dr. Peter Attia podcast on the VIRTA diet

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