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Low carbohydrate diets can work really well for type 1 diabetes. We know this. A plant-based low fat, high carbohydrate diet can also work really well for type 1 diabetes. Go figure.

Adults are entitled to choose whichever dietary pattern fits best with their life. As a healthcare professional working in nutrition, I will generally support a patient in whatever “diet du jour” they choose, until it’s not working.

So what about the individuals taking insulin who try a low carbohydrate (or plant-based high carbohydrate) diet and just “can’t hang with it”? Many people actually end up swinging back and forth between these two dietary extremes. They end up with wonky blood glucose (BG) numbers, increases in binge eating behaviors, and way more psychological stress.

Does this make them weak? No. Do we ever hear about them? No, because it’s bad publicity for the low carb tribe. Most studies on restrictive diet interventions, whether for weight loss or diabetes control, show deteriorating compliance at the 1-year mark if not earlier, so it’s of no surprise when the struggle occurs.

First off, it’s important to note that trying to adhere to a very restrictive ultra-low carb diet like the Bernstein method can put a tremendous amount of pressure on some people with type 1 diabetes, especially if they’ve dealt with any sort of eating disorder issues.

If you scour online forums, you’ll see individuals who’ve battled past eating disorders who are concerned about embarking on such a restrictive diet as they KNOW this will trigger disordered thoughts and behaviors and don’t ever want to go back to that place.

According to the National Association of Anorexia Nervosa and Associated Disorders, eating disorders have the highest mortality rate of any mental illness, so this is not something to scoff at or overlook. You’ll read about people with diabetes who “can’t stop binging during a hypoglycemic episode” or are asking “how to stop the carb cravings.” Of course, there will be a cacophony of responses, ranging from “you just do it,” to “I take meds to help with the cravings,” to “get over it, carbohydrates are poison.” Ouch.

While I was in my dietetic internship at Duke University, I met a person with diabetes who had morbid obesity and who had participated in Dr. Eric Westman’s “low carb clinic.” They did well on that regimen until they ended up gaining back all the weight plus some, along with a resurgence in their type 2 diabetes.

At that moment, my iron-clad nutrition paradigm started to shift, as the sadness and shame from “diet failure” was palpable. Most individuals would say they “didn’t try hard enough.” But when you meet an actual person and hear their story, you’ll learn there are many factors that play into their success with a specific dietary approach.

Even though I was moved by this experience, my practice philosophies still didn’t change in terms of my recommended dietary approach for type 1 or type 2 diabetes — low carbohydrate. Over the next few years as I worked in a pediatric and adult endocrinology clinic, I steered most patients toward the more severe end of the “low carbohydrate spectrum” and was enthralled by the ability of the low carb approach to produce a flat line continuous glucose monitor (CGM) tracing.

That was, until I worked with 10 young adults in a clinical trial (for my graduate thesis), who chose to participate for a total of 8 months: 3 months on the low carbohydrate diet (60 to 80g day), 2 months of a “washout” period back on their own preferred diet, and another 3 months on the “standard diabetes diet” of >150 g carbs per day.

Several of the subjects started to binge on food used to treat hypoglycemic episodes during the low carbohydrate diet, which was previously a nonissue for them. They said they felt “out of control,” and the flat line of the CGM when things were “good” was clouded by the hypoglycemia hangover.

By week 9 of the low carb diet, most subjects were struggling. This is no different than type 1 diabetes low carbohydrate studies or weight loss studies that show returns to previous behaviors as early as 6 months.

A 12-week carb-counting study evaluated people with T1D — some of whom were on a diet restricted to low carbohydrate eating (75 grams per day) and some who were not. At the end of the study, the researchers conducted interviews to see how the subjects felt. It was reported that food changed from being “a pleasure to chemistry.” The participants on the low carb regimen reported experiencing mealtime insulin resistance, but also saw positive results overall.

As individuals, it’s easy to sit in judgment over those who don’t prefer this or that diet, as we all have biases that cloud our judgment. If low carbohydrate has worked for you, then it’s self-preservation to say that the person who failed low carbohydrate “just didn’t try hard enough.”

For individuals whose low carbohydrate diet didn’t produce the results they anticipated, these four things could give some insight into the struggle:

1. The protein problem

When eating very low carb or “keto” over time, you may start to see high post-meal glucose numbers resulting from digesting so much protein. Many studies have sought to create a standardized method for insulin dosing for protein, but to date there is no recognized “best practice.”

The old school Bernstein method advocates covering half the grams of protein as “carbohydrate” with regular insulin, but many patients today are on rapid or ultra-rapid acting insulins via insulin pump, so this method may not be effective.

From clinical experience, I find that dosing insulin for high protein meals is not predictable or easy, and can even cause more BG variation than a mixed meal (with moderate carbohydrate content) at times.

2. Rigid dietary restriction vs. flexible eating

There is strong research supporting a more flexible eating approach versus rigid. The mental struggle that comes with a rigid diet has also been studied specifically in the diabetes world. And we know that diabetes distress is a real thing that can already have a big impact on people’s lives.

Swearing off any one food group can lead to dichotomous thinking or the “what the heck effect” — the moment you “slip” and enjoy some carb-laden food, you can’t stop and then decide to throw in the towel because you’ve “already failed.”

The possible weight gain and cyclical dieting caused by trying to be “too low carb” may cause more cardiometabolic harm than being able to maintain control with less effort at a more moderate amount of carbohydrate intake. This is highly individual, but something to consider if you’re struggling.

3. Binge eating

Taking black-and-white thinking on carb consumption to the extreme can lead to binge eating disorder symptoms, common in many people with type 1 diabetes. For someone who has struggled with an eating disorder, great care needs to be taken to avoid triggers like the notion that they are “on a diet” rather than a long-term approach to balanced eating.

Of course for those with type 1 diabetes, disordered eating patterns are complicated by hypoglycemic events.

It’s hard enough to control your eating in a state of euglycemia (steady blood sugar), but trying to impose specific food restrictions during blood sugar excursions can set you up for an even bigger binge.

4. Poor treatment of lows

When an individual with type 1 diabetes is taught how to administer insulin, how to check blood glucose, and how to treat a hypoglycemic event, they are often still taught the traditional “Rule of 15”. This states that if blood glucose is less than 70 mg/dL, you should consume 15 grams of fast acting carbohydrate like glucose tablets or juice, wait 15 minutes, then recheck blood glucose. At least one study has shown that using a body weight-based approached to treat lows, 0.3 g/kg glucose, is more effective and could also be considered.

People on strict low carb diets want to avoid the sweet treats and junk foods often used to treat lows at all costs. So they may try to treat their lows with the least carbohydrate-rich options.

The problem here is that many of the foods they choose to treat contain too much fat, which slows down digestion of carbohydrate and increases the time it takes to increase the blood glucose. This can leave an individual with a number that continues to drop despite adequate treatment and often results in overtreatment.

Regardless of your dietary pattern, treating lows with high carbhohydrate pure glucose or glucose/fructose is the best choice to resolve a low episode in a timely fashion without overtreating.

If your low carb diet is disappointing, you could try the following:

Consider ‘lower carbohydrate’ versus strict low carb

Shoot for a total of ~90 to 130 grams per day. You have permission to follow whatever dietary pattern fits best with your life and health goals. Sometimes your insulin-to-carb ratios will actually get stronger while on low carbohydrate, which is disappointing to many, as this results in taking more insulin for fewer carbs (but still overall less insulin than a high carbohydrate diet).

For any diet, I encourage the individual to do a lot of introspection and see if their methods are working for them. If they cannot continue with said approach forever and ever, something needs to change.

Improve the quality of your carbs

Aim for whole foods, rich in fiber to help buffer glucose spikes that result from carbohydrate-containing foods. Add protein and fat to your meal to further delay gastric emptying and help insulin timing with the “mixed meal.”

Aim for most of the carbohydrates you consume to be vegetables and fibrous fruits/grains with minimal highly processed grains and concentrated sweets that will send anyone’s blood glucose through the roof. See here and here for more specific tips on this.

Spread carbs throughout the day

Keeping carbohydrates to ~30 grams per meal rather than eating 60 grams in one sitting is a much better way to limit post-meal BG spikes. This would allow for a serving of starch or fruit at each meal if desired, both which can be nutrient dense and beneficial to overall health.

Depending on your age, weight, and activity level — which all contribute to insulin sensitivity — you may find you do better with 20 grams per meal of carbohydrate or do equally as well with 40 grams.

Take a week or two to track your carbohydrates, make sure your counts are on target (use MyFitnessPal.com or Cronometer.com to “recalibrate” your carb counting skills), and compare your insulin doses to BG numbers. It may be that in order to dial in your control, your insulin doses need to be tweaked or carbohydrate counting skills need to be refined.

I’d always encourage you to work with a diabetes educator who can provide “another set of eyes” if you would find that helpful. Using a CGM if available to help understand spikes in blood glucose after certain foods can be really helpful to improve insulin dosing.


Christina Crowder Anderson is a certified diabetes educator and pediatric registered dietitian nutritionist. She takes a no-nonsense, evidence-based yet open-minded approach to nutrition in her virtual private practice. In her leisure time, she enjoys spending time with her husband and her dog Cooper, along with cooking and judging Junior Olympic/NCAA gymnastics.