When I look back at previous blogs I wrote about weight management several years ago, I – like many healthcare professionals – tried to boil the solution of weight loss down to a simple equation of fewer calories in/more calories out. We know now that the body and the systems that drive a person to eat are much more complex and humans are largely programmed to gain weight or at least maintain a balance with a weight “set point.” Adaptive mechanisms of the body make it a challenge to achieve a sustained weight loss.
It is important to understand the many factors that cause and perpetuate why a person is living with obesity, such as genetics, environment, trauma, food security, complex brain chemistry and drive, all of which make it difficult to maintain weight loss. This can be even more difficult when living with diabetes, as meal planning and medication are usually involved.
Why strive for a healthy weight?
The goal of obesity management should be to improve health and well-being and not just about weight loss. Body mass index and waist circumference, although not perfect indicators, give us a way to measure being overweight or obese.
There is no doubt that obesity has increased in Canada. Since 1985 it has gone up in adults from 6.1% to almost 20%. Obesity can increase the risk of cardiovascular disease, cancer (colon, esophageal, post-menopausal breast cancer) and shorten life expectancy by 6 to 14 years. As well, it increases the risk of developing diabetes and osteoarthritis. So, striving for a healthy weight is good for your health. Maintaining a weight loss of ≥5% of total body weight can reduce cardiovascular risk and improve the body’s ability to lower blood glucose levels.
Weight loss and the brain
The brain balances many complex pathways when it comes to weight loss and eating. Part of the brain receives hormonal messages from the gut (for example GLP-1) that signal when food has been ingested, to give you a “full” feeling and to tell you at some point to stop eating. Other parts of the brain get a real “reward” signal from seeing, tasting and eating food, and will drive a person to eat even if they are full. Another “thinking” part of the brain tries to make “logical” decisions about eating, but functions best when the brain is not tired or stressed. For example, overeating can often happen in the evening when a person is fatigued and suffering from the stress of the day, so this part of the brain is not working as well.
Fat cells also give off chemical signals that tell a person to consume more if they have lost weight by reducing calories. These signals can be present months after weight loss, making it hard for a person to keep the weight off.
Understanding this complex nature of eating and obesity can help individuals living with obesity and their caregivers to select the best combination of nutritional, behavioural, pharmacological, or surgical approaches to weight management.
Diets: which ones work?
The very word “diet” is often perceived as a temporary fix. That is, you lose the weight but then carry on eating as you did before. However, making sustainable changes to your way of eating (i.e. your meal plan) is more likely to result in weight loss that stays lost.
If you are taking insulin to treat your diabetes, it is advisable to consult with a registered dietitian before making any changes to your meal plan. A sudden and sharp decrease in carbohydrates which many “quick fix” diets propose, can result in low blood glucose levels if insulin is not adjusted properly.
So which diets actually work? Those that are largely plant-based – such as vegan or calorie-restricted vegetarian– promote both weight loss and improved glucose control. The Mediterranean diet is low in red meat and high in fruits, vegetables, nuts, seeds, legumes, cereals and whole grains with fats supplied as olive oil. This diet helps reduce the risk of heart disease and improve blood glucose levels.
Popular weight-loss diets – such as Atkins, the Zone, Dean Ornish, Weight Watchers and Protein Power Lifeplan – are, over time, no more effective than a more straightforward approach that combines calorie restriction and consumption of lower-fat foods. Typically, it is difficult to stay on these popular diets for very long as they are not very satisfying.
To help people with diabetes stay on track with their weight, most diabetes education centres advise the following three principles:
To help people with diabetes stay on track with their weight, most diabetes education centres advise the following three principles:
- Consult Canada’s Food Guide
- Use the plate method for portion control
- Eat foods that have a low glycemic index
Other suggestions can be found in the Diabetes Care Community’s diabetes diet articles and posts.
Medications and Weight Loss
Diabetes Medications
Some medications that treat diabetes can lead to weight gain. It is important to speak with your diabetes team to see if these can be adjusted to different medications that do not cause weight gain or ones that cause weight loss.
Typically, medications that boost insulin (for example, gliclazide and glyburide) can cause weight gain, as can meal-time insulin (bedtime or basal insulin do not cause as much weight gain). Metformin and DPP-4 inhibitors are weight neutral, meaning they do not impact weight. SGLT2-inhibitors (Invokana®, Forxiga® and Jardiance®) cause some weight loss, as a result of more glucose (and therefore calories) leaving via the urine.
GLP-1 is one of the gut hormones mentioned earlier that signals the brain when eating. GLP-1 receptor agonist medications (Victoza®, Saxenda®, Trulicity®, Ozempic® and Rybelsus®) also lead to weight loss by signaling the brain that you are full and causing a decrease in uptake of calories, as well as other central mechanisms. Although the GLP-1 receptor agonist medications were designed for the treatment of diabetes by lowering glucose, they also cause weight loss both in people with and without diabetes, particularly at higher doses. So, for example, liraglutide (Victoza®) at doses of 1.2 mg and 1.8 mg are used as a diabetes medication, but at 3 mg, liraglutide (Saxenda®) is used in individuals with and without diabetes as a weight loss medication.
Semaglutide (Ozempic®) appears to be even more potent in helping people lower glucose and also lose weight, and is used at 0.5 mg and 1 mg in people with diabetes. Recent studies at higher doses were very effective in helping people without diabetes lose weight. However, its use for weight loss in people without diabetes is still in the development stage. The weight loss achieved with the use of GLP-1 receptor agonists, especially in higher doses, has been as high as 15% to 20% of body weight.
Medications approved for weight loss in Canada
Medications in Canada that are approved for weight loss must show a decrease in weight of at least 5% of total body weight and an improvement in obesity-related complications, such as progression to diabetes. There have been advances in the area in the past few years.
Orlistat
This medication interferes with the absorption of fat in the diet. It is taken three times a day with meals. It can cause a number of side effects such as flatulence and greasy stools, especially if fat is consumed in the diet. Because of this, and the outcome of generally less weight loss than other medications, its use is limited.
Liraglutide – 3 mg (Saxenda®)
As mentioned in the previous section, this medication at 3 mg is approved for weight loss in people with and without diabetes. It is injected daily and, on average, leads to an 8% weight loss, but can range from 5% to over 10%. This medication mimics one of the gut hormones that leads a person to feel fuller. The main side effect is nausea. As a weight loss medication, it is generally not covered by provincial formularies; however, at the lower dose used for treating diabetes, it may be covered.
Naltrexone/bupropion
It is interesting that a combination medication of an antidepressant, which is used to treat depression, and an opioid blocker, which is used for the treatment of alcohol and opioid dependence, works to help people with weight loss. Neither of these medications leads to weight loss on their own. This combination medication seems to interfere with the “reward” centre in the brain and reduces cravings, leading to weight loss. It is taken daily as a pill and may be used in people with diabetes. However, a number of other medications must not be taken at the same time as the naltrexone/bupropion combination. Find more information about these medications here.
Commercial products and programs in obesity management
Many commercial products that promote weight loss are available, but it’s important to be a savvy consumer to distinguish amongst them. The Obesity Canada Guidelines provide excellent information on this topic
What about surgery?
For people living with diabetes who are in the very obese range, bariatric or gastric bypass surgery has been shown to be effective over the long term for weight loss and improved diabetes outcomes. People who are interested in pursuing this option must first consult with their family doctor and then be referred to a specialist. Usually, the person is assessed by a team, and there is a wait time and counselling involved. Although some provincial public health plans cover the costs associated with weight loss surgery, others do not; ask your healthcare team if weight loss surgery is covered in your province. As an alternative, some people seek private approved clinics.
Managing obesity may seem overwhelming, but it is important to discuss your goals with your diabetes healthcare team so that they can work with you on the best option for your needs.
