Diet Fad or The Future of Health? Keto & Intermittent Fasting for Blood Sugar Management


Sugarbreak Editorial

The Keto Diet and Intermittent Fasting (IF) have become two of the most popular eating regimens and dietary protocols in the past few years. At first glance, they almost appear too good to be true—promising the world in terms of health and longevity in trade for a little self-control (okay, a lot of self-control). But they’ve stuck around and science has proven that they’re more than just fads. This got us wondering: When it comes to blood sugar and overall health, do these diets actually deliver the hard system reset they promise? What’s the catch with keto and IF when it comes to diabetics and individuals looking to self-manage their glucose levels? 

As the research grows, there’s no doubt the science is starting to pile up in favor of Keto and Intermittent Fasting as two potentially beneficial avenues for natural blood glucose management.  Of course, neither is a magic wand and it’s easy to cherry-pick science (after all, who doesn’t want to eat everything you want one day and just cut back a little the next?). So, with clean slates at the ready, we explore the good, the bad, the false, and the “really?!” of embarking on Keto and Intermittent Fasting as a means of managing your blood sugar.

What is Keto?

The Ketogenic (or Keto) Diet is a high-fat, adequate-protein, and low-carbohydrate diet that forces the body into a state of ketosis—a situation where the body begins to burn fat rather than carbohydrates for energy. Our bodies are smart; they know that glucose is the most premium source of energy, so they will always choose carbs first to burn through. Therefore, only in the absence of glucose will your body defer to fat. In short, the goal of Keto is to make your body use fat for fuel, shifting from sugar (glucose found in carbohydrates) to ketone bodies (produced in the liver from stored fat). As a result, this can help you lose weight and balance out your blood sugar. (Harvard Health).

It’s important not to confuse dietary ketosis with diabetic ketoacidosis, a condition triggered by low blood sugar and very low insulin where ketones accumulate, which can cause a coma or even death.

How does the keto diet work? Since keto consists mostly of high unsaturated or saturated fats (avocados, nuts, seeds, butter, and coconut oil), lean or fatty proteins, and low net carb vegetables, there are fewer opportunities for diet-provoked glucose spikes and crashes. In fact, research shows that people with type 2 diabetes who follow a keto diet have lower blood sugar, lose weight, rely less on medication, and have lower A1c levels after a year. For individuals with type 1 diabetes, there’s less research in support of a keto diet, but a small study (here's a link to that small study) found that it did help to lower their A1c levels, too. However, if you have type 1 diabetes, it’s important to  consult with your doctor before making changes to your diet.

How do the experts weigh in? According to Sugarbreak advisor and Registered Dietitian, Carlyn Rosenblum, MS, RD, CLC, the keto diet helps to stabilize blood sugar levels because you are cutting out foods (carbs) that have the largest effect on blood sugar levels. Additionally, because the diet is so high in fat it helps to keep blood sugar stable and satiety levels high. However, you should be mindful of the types of fats you are including while on keto and opt for omega-3 (salmon, tuna, sardines, walnuts, chia seeds, hemp seeds) and unprocessed monounsaturated fats (olive oil, avocado, nuts/seeds). While fat has little impact on blood sugar levels, too much saturated fat—think a lot of red meat, full-fat dairy, butter, coconut oil, processed meats, and cheese—has been shown to contribute to insulin resistance.

The Takeaway: Keto might be a good short-term option for people with type 2 diabetes or pre-diabetes who want to lose weight and naturally get their blood glucose under control. However, some may find it hard to adhere to and there are potential side-effects to investigate (like brain fog, constipation, increased risk of kidney stones, mood fluctuations, increased cholesterol, fatigue, and the keto flu). That being said, the proof is in the keto (sugar-free) pudding because it sure does get results.

What is Intermittent Fasting?

Intermittent Fasting (IF) is an eating plan that restricts the period of time when you eat. Usually this means you fast anywhere from 8-18 hours, consuming less than 50 calories between your last meal and your next meal the following day. While there are a few different approaches—some methods restrict calories for specific time periods, others for entire days—the general idea is that you go without food for a period of time to give your digestion, hormones, metabolism, and body a break.

As a whole, fasting in some form or another has been around for centuries—whether for religious or health reasons—and studies on resiliency show small, short-term stressors (like cold exposure, heat exposure, and fasting) result in a more regulated, acclimated, and resilient body.

So, how does it work? Essentially, the goal of IF is to decrease insulin levels to a point where the body begins to burn stored fat for energy. When you don’t eat for a period of time, that’s (generally) what happens.

Research shows that the benefits of IF potentially include: weight loss, improved digestion, reduced bloating, decreased inflammation, improved mental clarity, better sleep, improved ability to curb sugar cravings, improved insulin sensitivity, longevity, and blood sugar control. However, one of the major dangers of IF is the risk of hypoglycemia, or low blood sugar. If you’re taking insulin, it’s imperative that you work with your doctor to ensure it’s safe for you to fast.

According to Rosenblum, gender also plays a role in the effectiveness of IF. Most of the studies showing the benefits of IF have been done on men. Women and men have very different hormonal profiles, and we know that prolonged fasting impacts women's hormones much more. Fasting can cause changes in estrogen balance, which impacts fat storage, hunger levels and other hormone levels. For women, the best approach is to start with a conservative "reverse fasting" schedule. Where you eat breakfast and lunch at your normal time, but move dinner up earlier (around 4 or 5pm). Reverse fasting helps to achieve the same benefits of a traditional 12pm to 8pm window, but without impacting blood sugar (and thus hormones).

As mentioned before, there are a lot of ways to do Intermittent Fasting. Here are the most common methods:

5:2 Plan Five days of eating and 2 days of fasting. During your fasting days, you eat whole foods and no more than 500 calories for women/600 calories for men.

1 Day On, 1 Day Off  Just what it sounds like: Eat normal for one day and fast (500 calories) the other.

16:8 Plan  Fast for 16 hours and eat your meals within the remaining 8 hour window. During fasting, you can have water, black coffee, and similar zero calorie liquids, but you don’t want to eat anything with sugar. The rule of thumb is that your body remains in a fasting state if you consume less than 50 calories.

20:4 Plan  Fast for 20 hours then eat within your 4 hour window. 

1 Fast Day  24 hour fast, once a week. Eat regularly for 6 days and then fast for 24 hours.

The Takeaway: Intermittent Fasting and Keto can help you lose weight and keep your blood sugar from riding a highs and lows rollercoaster. Regardless of the plan you follow, it’s important to track your blood sugar levels consistently and log the results. Over the years, research has proven that diet is an effective way to manage, prevent, and even reverse type 2 diabetes. That said, each body is different; the approach that works for you, whether it’s Keto, IF or another diet plan, may not work for someone else (and vice versa). Do your research, talk to your doctor, and make decisions that best serve you, your goals, and your individual needs.