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The hardest thing about trying to lose weight with type 1 diabetes (T1D) isn’t will power, it’s low blood sugars.

I am a personal trainer and lifestyle coach with T1D myself, and this is the No. 1 most common thing my coaching clients struggle with before we work together. To me, it seems obvious that insulin doses need to be adjusted across the board. But for some reason, people don’t know this, or are afraid, or don’t know when and how to do it.

Sure, weight loss with T1D can come with a heaping serving of recurring low blood sugars, but it doesn’t have to be that way.

Here we’ll look closely at why those lows come on so quickly — even before you see changes on the scale or in how your jeans fit — and what to do about it. We’ll also look at some essential weight-loss wisdom to help you reach your goals.

Here’s the thing: While we’re taught that our bolus (fast-acting) insulin covers our food and our basal insulin covers our background insulin needs, they can actually criss-cross a bit. And nothing reveals this more than when you suddenly make some healthy changes in your daily habits around food, exercise, alcohol, and other beverages.

“Any time you start cleaning up your diet and walking every day, there are two variables you’ve changed that are huge,” explains Jennifer C. Smith, registered dietitian and diabetes educator with Integrated Diabetes Services, that provides virtual care out of Wynnewood, Pennsylvania. “Your insulin dosing needs are likely going to change before you even notice any actual weight loss. You’re immediately changing how sensitive you are to insulin by adding exercise and reducing your need for insulin by reducing your total calories.”

Your insulin needs will start changing the very day you start eating fewer calories, eating more vegetables and fewer processed foods, going for a walk during your lunch break or after work, drinking your coffee black instead of sweetened, going to Zumba, or lifting weights.

The more habits you’ve set out to change, and the more dramatic those changes are, the more noticeable the impact will be on your insulin needs.

There’s a common fear throughout the Diabetes Community that our daily essential insulin doses are the reason it’s harder for people with T1D to lose weight compared to our non-diabetic peers.

But all living mammals need insulin. Insulin itself does not cause weight gain, nor does it interfere with weight loss.

“People think weight gain is the fault of insulin,” Smith confirms. “But it’s the same for people without diabetes: If any of us eat more calories than our body needs or have habits that lead to insulin resistance — which leads to needing more insulin — we are more likely to gain weight.”

Insulin, she reminds us, is a “storage hormone.” If you aren’t using the glucose brought into your body for immediate energy, insulin enables your body to store that glucose in your muscles or your liver for later energy use. If those stores are full, it’s stored as body fat.

“It’s not the insulin’s fault that you’ve gained weight after your diagnosis either; it’s more the misadjustment in the dose of insulin that’s the problem. Fine-tuning your insulin doses is critical for losing weight. And working towards reducing your total daily insulin needs — with healthy changes in your lifestyle habits — is going to help you lose weight,” Smith said.

Diabetic or not, we all have the same goals when it comes to achieving and maintaining healthy insulin sensitivity through our lifestyle habits.

So, how do you safely adjust your insulin doses when you’ve started making changes in your habits and thus increased your sensitivity to insulin while decreasing your body’s need for insulin? And when do you make those changes?

Smith told DiabetesMine that the low blood sugars you could experience from those healthy changes could start within just a few days of starting on your new weight loss goal. This means you’ll need to make small adjustments quickly with the support of your diabetes healthcare team.

“It starts with your basal insulin. You have to really have a good foundation — your basal rates or long-acting insulin dose are the foundation of your house. If you have it well-built, everything you build on top of it is going to work better. If the foundation of your house is off by even a unit or two of excess insulin, you’re going to have a very hard time keeping things in range.”

“First, you’re going to look at your overnight blood sugars. Are you having lows overnight? The goal is to adjust your background insulin so you’re not having lows or highs overnight — that means you have 8 hours of the day where you’re not taking excess insulin or consuming excess calories,” explains Smith.

If you are experiencing frequent lows during the day or night after initiating new habits for the sake of losing weight, most people will find a 5 to 10 percent reduction in your total long-acting background insulin dose is the first step, she said.

So for example, if you take 30 units of Lantus insulin daily, you would multiple 30 x .10 = 3 units. This means you would reduce your total long-acting insulin dose by 3 units. For a more reserved reduction, 5 percent would mean a 1.5-unit reduction.

While insulin pumps offer far more options when it comes to dosing adjustments, they can also make implementing changes seem a little more overwhelming.

“If you’re on a pump, you can look more closely at what times of day you’re experiencing more high or low blood sugars,” explains Smith. “While the 5 to 10 percent reduction in your total basal insulin is similar to those on injections, you have more control over which specific hours you make that adjustment.”

Smith says that while you could make a reduction across all basal rates as the simplest approach, you’ll likely fare better if you can pinpoint where the reduction is most necessary.

“What is your total basal insulin? A 10 percent reduction in 24 total units, for example, is 2.4 units less. But then you have to divide that across the board all day, and you’ll have to reduce every basal rate,” said Smith, referring to those who may have variable basal rates set on their pump.

She suggests making small changes and then monitoring closely to determine if there’s a particular period of the day when you’re having the most lows. “That may be evening or overnight — now you can see exactly where you can reduce your basal,” she said.

The trickiest part of reducing meal boluses is that having a low after you eat doesn’t necessarily mean the adjustment should come from your meal bolus. This is why it’s important to first reduce your basal rates, as Smith described.

“However, if you do feel like most of your lows are coming after eating, your insulin-to-carb (IC) ratio could need a big change if you’ve gone from eating heavier, carb-loaded meals to healthier meals with more vegetables, lean protein, and so on,” explains Smith.

“For example, if you used to always eat a huge sandwich for lunch and now you’re eating a salad, you may not need the same ratio anymore because the meal isn’t as high in fat and starch.”

Making a change in your IC ratios would start small, much like the 5 to 10 percent reduction in basals. If your current IC ratio is 1:8 (1 unit of insulin for every 8 grams of carbohydrate), you could make a slight reduction in your insulin dose by increasing the carbohydrate grams to 1:10, resulting in less insulin for the meal.

The process of reducing insulin doses to account for changes in your day-to-day habits is a very delicate juggling act. One week you may need to make that 10 percent adjustment, and then the next week or two you may see no changes.

What we all know for sure, however, is that frequent lows mean you’re getting more insulin than you need. The tricky part is determining exactly how much more and when.

As if losing weight isn’t hard enough, one of the biggest hurdles those of us with T1D can add to the list is preventing low blood sugars around exercise.

Smith offers two key tips: “The timing of your exercise matters most. You have a few options. If you exercise before eating breakfast, before you’ve taken any insulin for meals, you’re more likely to burn fat for energy instead of glucose because you’re in a fasted state. This creates more stable blood sugar levels during your workout.”

Or, she adds, you could exercise right after a meal.

“Exercising right after you eat means two things. First, you’ll need to cut your meal dose down significantly, by anywhere from 30 to 70 percent depending on the person, duration, and type of exercise. It also means you’re reducing your total daily insulin, which is a good thing. And it means you’re not eating extra calories just to fuel your blood sugar for exercise,” Smith said.

Of course, there are a great number of variables involved in blood sugar management and exercise. Taking good notes and making careful adjustments is truly the only way to figure out exactly what your body needs for each different type of exercise and time of day.

DiabetesMine offers extensive guidance here: Type 1 Diabetes & Exercise: What You Need to Know.

“It takes a long time to lose weight — regardless of diabetes,” emphasized Smith. “The human body does not like change. You get to a weight that you’re at for a while and your body gets used to that. It’s stressful to your body to lose weight — your body will do anything to resist it from happening!”

This is why slow weight loss is always more successful than a crash diet plan that produces big results too quickly, adds Smith. Your body will rebound right back to where it was before if you can’t sustain that stressful pace and whatever intense changes you made to your diet and exercise to create that fast weight loss.

“The reason diets most don’t work long term for most people is because they’re severe and inevitably short-term. If your plan is too low in calories or too rigid in what you can and cannot eat, most people will struggle to succeed with a plan like that.”

She poses this question to determine if your weight-loss diet plan is realistic: “Can you follow that diet until you’re 99 years old?”

The best diet is one that will accommodate you and your lifestyle, she cautioned.

“There is no one cut-and-dry plan that works for every single person. If there was, we would have this huge problem of diabetes diet and diabetes management solved!”

Personally, Smith says she eats her own plan that she jokingly refers to as “The Jenny Diet” — which includes dark chocolate every single day.

“The good majority of my day is all whole foods. How does your body respond to what you’re eating? If you can eat white bread every day and manage your blood sugar around that — and feel good — then you can enjoy your white bread!”

Smith uses her own body as an example again noting that she knows a high-carb lunch leaves her feeling lethargic and struggling with high blood sugars the rest of the day. Instead, she focuses her daytime meals on vegetables, hummus, some fruit, and other healthy protein sources.

“I enjoy my carbs later in the day — it works better for my energy and my blood sugars,” she adds. “Before you even start trying to lose weight, it may be time to look more closely at how you feel after the food choices you currently eat.”

Let’s get one thing out of the way right now: The weight-loss pills you can buy over-the-counter at your typical vitamin store aren’t ideal for those with T1D because they’re loaded with stimulants.

And what do stimulants do? They actually increase your blood sugar, usually by stimulating your liver to release more glucose, and thus increase your insulin needs.

Don’t fall for the marketing muck. These pills are not the answer.

That being said, there are a few Food and Drug Administration (FDA)-approved drugs that have helped people with T1D lose weight, explains Dana B. Roseman, another registered dietitian and diabetes educator on the team at Integrated Diabetes Services.

The tricky part, explains Roseman, is that most of these medications are intended for type 2 diabetes, which means as a T1D, you’d be using them “off-label” and thus likely paying out-of-pocket for them.

Symlin was one of the first drugs designed for type 2 diabetes — and was used regularly in T1D — that helps with weight loss, but you have to take it three times a day and it often comes with side-effects of nausea,” said Roseman.

Newer drugs that have shown to help with weight loss and insulin resistance include Victoza, Ozempic, Trulicity, and Xenatide — in the class of GLP-1 drugs.

GLP-1 drugs stimulate glucose-dependent insulin release from the pancreas, and reduce release of glucagon that counteracts insulin. This results in decreasing glucose output from the liver, which can lead to low blood sugars if you don’t titrate your insulin doses quickly when starting the drug. GLP-1s also slow down the digestion process, which lowers your appetite,” Roseman said.

Another category of diabetes drugs that do have an added side effect of weight loss are SGLT2-inhibitors like Invokana and Jardiance.

“These promote weight loss because you excrete excess sugar through your urine,” explained Roseman. “But they can lead to some tedious side effects like yeast infections, and an increased need to pee. It’s important to keep yourself well hydrated every day with this category of drugs. For some type 1s, there have also been cases of going into diabetic ketoacidosis (DKA) even with normal blood sugars. They don’t quite understand why this happens for some and not others. So it’s important to be very aware of whether you’re using this off-label.”

If you think an additional medication might help you improve your insulin sensitivity and support your weight-loss goals, the first step would be to discuss it with your doctor.

“Most endocrinologists these days are accepting of these drugs for off-label use in type 1 diabetes,” said Roseman. “The bigger issue is really that your insurance won’t cover it so it will be very expensive.”

At the end of the day, Roseman and Smith both remind us that no drug or trendy diet can compensate for essential healthy lifestyle habits. When you implement better habits around food, alcohol, exercise, stress, and sleep, weight loss comes, too. Just remember, even if it doesn’t come as fast as you wish it would, this is a long-term game you’re playing. Slow and steady wins the race.


Ginger Vieira is a type 1 diabetes advocate and writer also living with celiac disease and fibromyalgia. She is the author of “Pregnancy with Type 1 Diabetes,” “Dealing with Diabetes Burnout,” and several other diabetes books found on Amazon. She also holds certifications in coaching, personal training, and yoga.