Losing Weight with Type 1

Losing weight is hard for everyone, but it gets even more challenging for those of us with type 1 diabetes.  The Diabetes Control and Complications Trial (DCCT) published in 1993 and follow-up Epidemiology of Diabetes Interventions and Complications (EDIC) demonstrated that intensive glucose control delays and slows microvascular (retinopathy, nephropathy and neuropathy) and cardiovascular (heart attack and stroke) complications.  Cardiovascular disease (CVD) is especially important because it is the #1 killer of all people in the developed world and those with type 1 diabetes are no exception.

Another important finding of DCCT and EDIC is that intensive control is associated with weight gain and, at that time, more hypoglycemia.  Blood sugar control has been improving, but like the rest of the population, people with type 1 diabetes are becoming more overweight and obese.  In fact, there is emerging evidence that we are now more overweight than the general population.  This is important because death from CVD is associated with weight.

This puts us in a tough spot.  We want to avoid diabetes-related complications by controlling blood sugar but intensive control is associated with weight gain that puts us at risk for some of the same complications!  To stay healthy we need to maintain blood sugar control and try to maintain normal weight.  Here we discuss lifestyle strategies, medications and technology that can help with weight loss.

Lifestyle Modifications

To lose weight we must burn more calories than we consume.  When we burn fat, we generate ketones, which are a byproduct of fat metabolism.  It is important to recognize that with all of these strategies, you may have ketones because you are burning fat.  Diabetic ketoacidosis (DKA) becomes a concern when there are (1) ketones, (2) high blood sugar and (3) no insulin in your system.


The most effective diet for weight loss is the one that you can stick with.  It is very important to keep track of calorie intake and weight.  People start losing weight at different calorie set points, and unless you are aware of what that number is, it is impossible to be consistent.  As one loses weight, your insulin requirements will fall.  If doses are not modified one develops low blood sugar that may force eating of carbohydrates (15 grams carbohydrates = 60 calories).  One can stay ahead of this process by dropping all doses (say 5-10%) as weight drops. With successful weight loss, you get to spend less on insulin!


Exercise is important for optimizing the performance of your heart and maintaining muscle.  Guidelines for people with type 1 diabetes suggest 60 minutes of moderate- to vigorous-intensity aerobic activity daily.  Despite these benefits and recommendations, burning enough calories with exercise to lose weight is very hard.  For example, to burn off 1 Oreo cookie (53 calories) you would need to go up and down 10 stairs at least 24 times!  Additionally, if one develops low blood sugar during exercise, there may be a need to consume carbohydrates which may entirely remove the calorie expenditure from exercise.



Normally, Amylin, a peptide hormone is co-secreted by beta cells along with insulin.  Amylin slows gastric emptying and causes a feeling of fullness that can reduce appetite.  A synthetic form of Amylin called pramlintide (brand name Symlin) was approved in 2005 for patients with type 1 diabetes.  In clinical trials, users had a 1.1kg (2.4lbs) weight loss as opposed to 0.6kg (1.3lbs) weight gain in the control group.

GLP-1 Agonists

GLP-1 is a peptide hormone produced in the gut and brain, which increases insulin secretion, decreases glucagon and slows gastric emptying.  Multiple synthetic forms have been developed for use in type 2 diabetes.  All studies in people with type 1 diabetes have shown a significant weight loss.  In one study of daily Liraglutide injections participants with type 1 diabetes lost an average of 3.1kg (6.8lbs) over 1 year.

SGLT2 Inhibitors

SGLT2 is a protein that helps the kidney reabsorb glucose.  Oral medications have been developed to block SGLT2 and increase the amount of glucose excreted in the urine.  These medications have gained notoriety because they increase the rate of genital infections and DKA, which can occur with a normal blood sugar.  Because DKA can occur with normal blood sugar, it is important to always have some insulin-on-board.  In a 1-year study of Dapagliflozin 10mg participants with type 1 diabetes lost around 4.5% body weight.

Automated Insulin Delivery

Insulin pumps manufactured by Medtronic and Tandem can suspend insulin delivery in response to predicted hypoglycemia.  Traditionally hypoglycemia is treated with carbohydrates.  People aiming for tight glucose control may ingest significantly more calories treating lows.  By suspending insulin and avoiding lows, it is predicted that fewer carbohydrates would be ingested.  Often, however, people still take carbohydrates in response to pending low blood sugar despite insulin suspension.  This may be required if there is just too much insulin-on-board, but it is likely that fewer carbohydrates are needed.

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