ice with cherry on top

There are few diseases where lifestyle plays a greater role in both prevention and treatment than in diabetes type 2 and obesity. Changing lifestyle can turn out to be one of the best and most effective health investments.


After the incidence of type 2 diabetes has gradually increased over the past few decades, it appears that the trend is finally reversing. New cases of diabetes were reduced by a third in the period 2009 – 2014 (1). It is still somewhat uncertain what is the cause of the positive development, but the researchers behind the study believe that it has a connection with changes in lifestyle. Diabetes type 2 is one of the diseases where lifestyle has the most to say both in terms of preventing and also treating the condition. Most cases of type 2 diabetes can therefore be avoided or delayed through a healthy lifestyle.

Diabetics are at increased risk of a number of health problems including eye disease, kidney disease, stroke, depression, dementia, foot ulcers, polyneuropathy and infections. 75% of diabetics die from ischemic heart disease and people with diabetes generally have a shorter life expectancy. Obesity and overweight are one of the biggest risk factors for the development of type 2 diabetes. Today, it has become abnormal to have a normal weight. 7 out of 10 adult Norwegians are now overweight (2).

Being overweight and obese increases the risk of a whole range of health problems. Obesity is now becoming the most common cause of cancer. In addition, the chances of getting type 2 diabetes, stroke, heart disease, osteoarthritis of the knee and hip, reflux problems, depression, gallstones, hernias, sleep apnoea, high blood pressure, pregnancy complications and shorter life expectancy increase. But don’t despair. Obesity and diabetes type 2 can be influenced to a large extent through lifestyle.

Development of type 2 diabetes

It often takes a long time to develop diabetes type 2. The process usually begins with insulin not working normally, which is called insulin resistance. Insulin plays a major role in regulating blood sugar and help the sugar in the blood to enter the cells. When insulin binds to receptors on the cell membrane, signals are sent down into the cell that cause small vesicles with glucose transporters to move out towards the cell membrane and fuse with it. In this way, “openings” are created in the cell membrane that sugar in the blood can use to enter the cell. Eventually, the pancreas must produce more and more insulin to keep blood sugar down to normal levels. Over time, insulin production becomes lower, blood sugar begins to rise and eventually type 2 diabetes becomes a reality.


Lifestyle treatment is one of the cornerstones of diabetes management and it is particularly important to start early with addressing relevant lifestyle factors. Diabetes and blood sugar are affected by a number of lifestyle factors such as weight, diet, physical activity, sleep and nicotine/tobacco.

Weight reduction

For many people with newly diagnosed type 2 diabetes, weight reduction is the only (and perhaps also the most difficult) intervention needed to get blood sugar back to normal. It has been observed in several studies that in overweight people with type 2 diabetes who undergo bariatric surgery, about half achieve reversal of diabetes type 2 in the first 1-5 years. Around half of these, however, develop diabetes again after around 8 years (3).

a man holding his stomach with his hands

Do we see the same effect with “normal” weight reduction? In a study of diabetics who had had type 2 diabetes for less than 6 years, it was found that the greater the weight reduction the participants achieved, the greater the likelihood that they could reverse the condition and achieve normal blood sugar after 12 months (4). This is the first study of its kind, but gives hope that tablet treated type 2 diabetes can be reversed, at least in the short and medium term.

Why is weight reduction so important in type 2 diabetes? One of the main reasons is that obesity affects both of the main mechanisms of type 2 diabetes, namely insulin sensitivity in body tissue and insulin secretion from the pancreatic nucleus. Studies show that a weight loss of around 5-10% is enough to increase insulin sensitivity in the cells and also improve insulin secretion from the pancreas (5). Further weight reduction will be able to give even better results. A weight reduction of 10% or more not only increases the chance of reversing diabetes, it also reduces the risk of developing heart and vascular disease (6), from which approx. 75% of all diabetics die.

For a long time, research has been conducted into which strategies are most effective for achieving weight reduction. At the rehabilitation center where I work, we receive many patients who want to achieve weight reduction during their stay. Some expect the kilos to disappear primarily in the gym. However, it is what happens in the dining room that is of the greatest importance for whether weight reduction is achieved.

What should I eat?

With regard to what is the optimal diet for losing weight, it seems to be more important that you maintain a daily calorie deficit, which over time will lead to weight reduction. There is good documentation that both a fat-reduced and a carbohydrate-reduced diet can be used to lose weight (7). A caloric intake that is approximately 500kcal lower than what is needed to maintain weight is recommended, which can lead to a weekly weight loss of around 500g.

Many people find it challenging to count calories and get an overview of their daily calorie intake. Recently, an interesting study showed that it is entirely possible to lose weight even without counting calories, even without trying to limit calorie intake in any way.Instead of limiting calorie intake through calorie counting, the researchers here focused on limiting which foods were eaten (8).

The menu that the participants in this study followed consisted of a reduced-fat version of a “whole food” plant-based diet: Fruit, vegetables, legumes, whole grains and limited intake of nuts, avocado, olives and other high-fat plant products. The average weight in the group was reduced from 94kg to 82kg (12kg) within six months. According to the researchers behind the study, it is the largest weight reduction reported in the literature in weight reduction studies that have not had restrictions on calorie intake.

Foods that contain a combination of a lot of fat and sugar seem to be particularly unfavorable for weight as they are not only very calorie dense but also increase appetite and reduce the feeling of satiety, i.e. exactly the opposite of what is desirable for weight reduction (9).

How often should I eat?

Is it best for weight loss to eat few or many meals? For several years, it was often recommended to eat many small meals (4-6) spread throughout the day. However, larger summary studies show that 4-6 meals do not result in greater weight reduction compared to 2-3 meals (10). A number of larger epidemiological studies even seem to suggest that fewer meals may be preferable, as for example observed in “Adventist Health Study 2”, where fewer meals were associated with (greater) weight reduction over 7 years (11). In tablet-treated type 2 diabetes, better insulin sensitivity has been observed with two meals versus six meals per day.

When should I eat?

silver round wall clock at 7 00

A number of studies suggest that the time of day when you consume the majority of your daily caloric intake or have your largest meal seems to be able to affect your weight. In “Adventist Health Study 2”, eating breakfast, having breakfast as the largest meal of the day, and the longest fasting period between the last meal of the day and breakfast the next day were associated with (greater) weight reduction. Another study showed that those who ate their largest meal before 3 pm had a greater weight reduction than those who ate their largest meal after 3 pm (12). In a summary study which examined the effect of the timing of food intake on weight and diabetes, it was found that it seems that it is most beneficial to consume the majority of food earlier in the day (13).

Other factors affecting weight

Psychological factors associated with successful weight loss and maintenance of weight loss include (14):

  •  Inner motivation
  •  Self-efficacy
  •  Self-regulation (e.g. regular weighing, and checking that planned measures are followed)
  •  Avoid a rigid eating pattern where a number of foods are “forbidden”
  •  Positive body image

Studies on the connection between physical activity and weight show somewhat varying results (15,16). Traditionally, physical activity has been recommended primarily as an aid to maintain weight loss, but also to avoid muscle loss during the actual weight reduction (strength training). In order to use physical activity to lose weight, a number of studies show that the activity level should be at least 60 minutes a day (17).

Nutrition for diabetes

Diet is one of the most important factors in self-treatment of type 2 diabetes. According to national dietary advice for diabetes type 2, the following diet is recommended:

  • Plenty of vegetables
  • Daily intake of berries and fruit
  • Plenty of legumes (beans, peas and lentils)Wholegrain products with a lot of fiber, whole grains and kernels
  • Fish/seafood and poultry to a greater extent than red meat, and pure ingredients rather than stuffing products
  • Low-fat dairy products
  • Cooking oils and soft/liquid margarine, nuts and kernels as fat sources
  • Limited intake of all types of added/free sugar, including fructose (max 50-70g/day), and moderate use of energy-free sweeteners
  • Limited amount of salt

Mediterranean diet

The Mediterranean diet is a diet that is inspired by the eating habits of Greece, southern Italy and Spain. It includes an abundant intake of olives (oil), pulses, whole grains, fruit and vegetables, as well as a moderate/high intake of fish, a moderate intake of dairy products and a low intake of meat. The diet has been researched for a long time and appears to provide a number of health benefits, including a reduced risk of cardiovascular disease, type 2 diabetes and possibly also a reduced risk of cancer, dementia and depression. Two of the world’s five blue zones (areas with higher life expectancy) are located around the Mediterranean, and studies also seem to show a reduced risk of early death with a typical Mediterranean diet.

When it comes to diabetes type 2, studies show that those who eat most like a traditional Mediterranean diet have about a 25% reduced risk of developing diabetes type 2 compared to people who score the lowest in relation to this diet (18). The Mediterranean diet is rich in unsaturated fatty acids, unrefined carbohydrates and legumes, all of which are beneficial for people with type 2 diabetes.

Vegetarian diet

A well-balanced plant-based diet seems to be the most optimal diet for type 2 diabetes (19), and there seems to be a gradually reduced risk of type 2 diabetes the more plant-based the diet is. With a totally plant-based (vegan) and also lacto-ovo vegetarian diet, the risk of developing type 2 diabetes is roughly halved compared to a normal diet, also after adjustment for relevant factors such as weight, physical activity, sleep, screen time, etc. (20)

bowl of vegetable salads

An important reason why people who eat a plant-based diet have a lower risk of type 2 diabetes is that the more plant-based the diet, the lower the risk of overweight and obesity. However, there are also elements in the plant-based diet that in themselves affect blood sugar and insulin sensitivity in a positive direction and at the same time prevent late complications of diabetes.

Both whole grains, nuts, legumes as well as fruit and vegetables are associated with a reduced risk of developing type 2 diabetes (21). A “whole food” plant-based diet maximizes the intake of preventive foods and at the same time excludes foods associated with an increased risk of diabetes, primarily processed and red meat. Studies suggest that as the intake of animal proteins increase, so does also insulin resistance (22).

Studies as far back as the 1930-50s (23,24) have shown that a diet rich in unrefined carbohydrates and low in fat is beneficial in the treatment of diabetes and accompanying complications. Already in the 1970s, an interesting study observed how such a dietary pattern could normalize blood sugar in people with type 2 diabetes within a few weeks (25). Many of the participants in the study had had diabetes for 10-15 years, but had normal blood sugar again after only 2-3 weeks on this diet. Calorie intake was adjusted so that the participants did not lose weight during the study. In all these years of diabetes and insulin treatment (tablets for diabetes type 2 came later) many of the participants seemed to be only 2-3 weeks away from normal blood sugar. Several of the participants who did not achieve normal blood sugar during the study were so inspired by the participants who were able to stop taking insulin that they continued with the same diet after the study. Several of them were eventually able to stop insulin treatment.Later studies have produced similar results, with a significant reduction in long-term blood sugar and the need for diabetes medication with such a diet (26).

Furthermore, such a diet reduces the risk of developing cardiovascular diseases, which many diabetics develop and 3 out of 4 diabetics die from. Around 20-40% of diabetics develop chronic kidney disease. Although some research remains before a final conclusion can be drawn, results so far suggest that a diet with a lot of plant products and little animal products is beneficial for this condition (26).

Polyneuropathy is another late complication of diabetes. Few studies have been done on the effect of diet on the condition, but a couple of smaller studies have shown significant and lasting symptom reduction with a plant-based diet (26). In general, improving blood sugar will often have a positive effect on this condition.

Legumes are one of the very best foods for managing diabetes. No other food group contains as much fiber, which is beneficial for regulating blood sugar. In addition, they are rich in “diabetes-friendly” proteins and can often replace animal protein sources. Legumes have a special property in that they do not only affect blood sugar during the meal you eat them. Studies have shown that those who eat beans, lentils and other legumes have a lower rise in blood sugar also at the next meal, and even during breakfast the next day (27). This “second meal” effect shows how useful legumes can be in terms of regulating blood sugar.

Given the many health benefits that a plant-based diet has in the prevention and treatment of diabetes, it is not surprising that earlier this year the American Association of Endocrinologists came out and recommended the following for its members: “Lifestyle treatment [for type 2 diabetes] begins with dietary guidance. All diabetic patients should work to achieve and maintain a normal weight through a predominantly plant-based diet” (28).

Physical activity

Physical activity is one of the most important ingredients in diabetes treatment and the level of activity is one of the strongest predictors of mortality (all cause mortality) in diabetics, on par with smoking. Nevertheless, a Norwegian study showed that only 1 in 10 diabetics are as physically active as recommended, namely 30 minutes a day. Physical activity not only prevents the development of type 2 diabetes, but regulates blood sugar, improves insulin sensitivity and prevents late complications and the risk factors for these. During physical activity, glucose uptake in the muscles increases by up to 500% via insulin-independent mechanisms over the next two hours. Furthermore, insulin sensitivity improves over the next 48 hours. In the case of shorter training sessions (approx. 20 min), the improvement in insulin sensitivity will last somewhat shorter, approximately 24 hours, provided that the activity is of high intensity.

a woman walking down a path in the woods

To achieve the best possible effect, the activity should be either prolonged (> 60 min) or intense. This means that physical activity is a fresh commodity and it is recommended that no more than a couple of days pass between each training session. Both cardio training and strength training have a positive effect on type 2 diabetes. It also seems to be beneficial to include a short walk after food intake. In several smaller studies, it has been seen that people with diabetes had lower blood sugar if they regularly went for a short walk of around 10 minutes after food intake, especially after larger meals with more carbohydrates. Physical activity further reduces the risk of developing late complications, including stroke and heart attack and risk factors for these such as high blood pressure and high levels of fat. It is recommended to have simple carbohydrates readily available if you use insulin or other medications that have the potential to cause low blood sugar.


Smoking and possibly also snuff increases the risk of insulin resistance and diabetes type 2. In addition, smoking worsens both macrovascular and microvascular (retinopathy, neuropathy and nephropathy) complications of diabetes. Most diabetics die from heart and vascular disease and it is therefore important to reduce other important risk factors for heart and vascular disease, such as smoking.


6-9 hours of sleep is associated with a reduction in cardiometabolic risk factors, while reduced sleep worsens insulin resistance and blood sugar, increases blood pressure and the level of fatty substances in the blood (28). Larger population studies also seem to suggest that persistent sleep difficulties may increase the risk of developing type 2 diabetes. Even if you get enough sleep, it is also best for your blood sugar to sleep at regular times and preferably avoid shift work and activities that turn the circadian rhythm upside down.


Obesity and diabetes type 2 are relatively common health problems that many people often do not realize the seriousness of, largely because they creep up. Both increase the risk of developing a wide range of health problems, many of which are quite serious. In addition, the conditions entail a reduced quality of life and an increased risk of mental health problems. However, the two conditions are influenced by lifestyle, which is often the reason why people have developed type 2 diabetes and obesity in the first place. Many need good and close follow-up in order to manage to change important lifestyle habits such as diet, weight and physical activity. Only about 10% of diabetics meet national recommendations with regard to physical activity (30 min daily), and only 50% have a healthy diet most days of the week. However, by optimizing lifestyle through good follow-up and effective strategies, weight can be reduced as well as the need for diabetes medication and the risk of developing complications. In many cases type 2 diabetes may be reversed in (at least) the short and medium term with intensive lifestyle treatment.

The most important lifestyle factors for treatment of type 2 diabetes are:

  •     Weight reduction if overweight/obese
  •     A mostly “whole food” plant-based diet
  •     Regular physical activity – minimum 150-175min/week


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