How You Can Reverse Prediabetes By Timing When You Eat
The science shows that you can reverse prediabetes by timing what you eat. Why should you care? Because, as you'll soon see, there's a good chance that you're prediabetic, or have higher blood sugar than is healthy. If that's the case, you're in the danger zone, given that long-term health requires low and stable blood sugar levels, as you'll soon see.
There are many ways you can eat on an intermittent basis, as opposed to eating all day long and into the night. New research shows that such time-restricted feeding improves insulin, blood pressure and oxidative stress biomarkers, leading to a healthier, and perhaps longer life.
The good news is that restricting the time frame within which you eat is simpler than adhering to a diet, and perhaps more effective too. Let's delve deeper into this subject, first by learning why your blood sugar level is so important, the positive time restricted eating can have on blood sugar and why when you eat often times is more important than what you eat.
The Blood Sugar Problem
About 86 million Americans are prediabetic, says WebMD, meaning that their blood sugar level is higher than it should be -- dangerously high -- but not yet in the diabetes range. The CDC reports that more than 100 million Americans have prediabetes and diabetes. Given a population of around 320 million, that means that just below one of every three Americans have a sugar/insulin resistance problem, and it's not going away.
For both people in the U.S. and the rest of the world, the prevalence of prediabetes is increasing. Experts have projected that more than 470 million people will have prediabetes throughout the world by 2030 .
OK, so a lot of people have some sugar in their blood; why panic about that?
Well, let's take a look at some sugar numbers as presented by WebMD and the Life Extension Foundation (LEF). WebMD determines normal, prediabetes and diabetes levels using a general reference range representing the U.S. population, which are also the numbers your doctor would most likely adhere to.
Fasting plasma glucose test:
- Normal if your blood sugar is less than 100
- Prediabetes if your blood sugar is 100-125
- Diabetes if your blood sugar is 126 or higher
Hemoglobin A1C (or average blood sugar) test:
- Normal: 5.6% or less
- Prediabetes: 5.7 to 6.4%
- Diabetes: 6.5% or above
Based on its review of the pertinent research, The Life Extension Foundation thinks that the above blood sugar/glucose categorizations for normal, prediabetes and diabetes advocated by WedMD are too lenient.
LEF says that your risk for age-related chronic disease is far greater at these "normal levels" than has been previously recognized, and put the ideal fasting glucose should range between 70 and 85 mg/dL (3.9 – 4.7 mmol/L). (Go here for blood glucose conversion table.)
One team of researchers found that the risk of developing diabetes itself was increased more than seven-fold in people with fasting glucose levels of 105-109 mg/dL, compared with people with fasting glucose levels less than 85 mg/dL, says LEF, and point to the following risks associated with "normal" blood sugar levels :
Increased Health Risks in People with "Normal" Glucose Levels
Glucose Levels (mg/dL)
Developing Type 2 Diabetes
Up to 283%
Up to 130%
First-time Heart Attack
Need for Coronary Bypass or Stent Procedure
If you accept LEF's summary of the research marking 85 mg/dL as the highest acceptable fasting glucose, then I'd be willing to bet that your number is too high, if you want optimum health.
If you wish to optimize your health, the work of two research scientists will be of interest: Dr, Drew Duglan's work on Intermittent Fasting (IF), and Dr. Nimet Maherali's work on time-restricted eating. Let's examine each of these.
Reverse Prediabetes With Time Restricted Feeding
Drew Duglan, PhD. did his doctoral research on the cardiovascular implications of diabetes at Oxford University. He says that you can reverse prediabetes and diabetes as well by restricting the time window in which you eat, particularly if you do so earlier in the day to match your circadian rhythms.
Dr. Duglan arrives at this conclusion through a review of a rigorous, 5-week randomized crossover feeding trial on eight prediabetic men conducted by scientists at the University of Alabama, Birmingham. Participants in this study were asked to adopt one of two eating schedules:
- Early Time Restricted Feeding (eTRF) schedule consisting of a 6-hour eating window, wherein the last meal was consumed before 3:00 PM each day; or
- A 12-hour eating schedule.
After a seven week break, each participant switched over to the other schedule. The researchers wanted to gauge whether intermittent fasting has benefits independent of weight loss. Therefore, food intake and meal composition was matched across both eating schedules, and each participant was fed enough food to prevent any reductions in body weight.
Compared to participants on the 12-hour schedule, those on eTRF experienced four important biomarker improvements (the first two pointing to both insulin sensitivity and β-cell responsiveness):
- A decreased fasting insulin,
- A decreased level of insulin during an oral glucose tolerance test,
- A significant decline in systolic and diastolic blood pressure equal to anti-hypertensive medications, and
- Reduce levels of 8-isoprostane, a marker of oxidative stress.
I stress that these improvements happened when compared to a relatively small duration of eating cycles -- 12 hours; whereas, most of us eat and drink something from the moment we arise till we go to bed, a time period well in excess of 12 hours.
What about hunger?
A common critique of most TRF protocols is the assumed increase in hunger during the longer fasting periods. Let's face it, if you're hungry all the time, you won't do it. In this study, however, participants on the eTRF schedule scored lower on most subjective measures of evening appetite, such as the desire and capacity to eat, while ratings of satiety increased.
Interestingly, subjects actually reported that eating all their food within a 6-hour period was a greater challenge than enduring the 18-hour fast, highlighting the feasibility of these interventions in future settings inside and outside of the laboratory.
The role of your circadian clock
The study we've been examining wasn't just about assessing the health benefits of reducing a person's feeding window, but also when the feeding occurs - it incorporated both fasting and biological rhythms.
We each have many so-called circadian clocks that regulate metabolism in response to different nutrients and based on the timing of food intake. In a paper called, Circadian clocks and insulin resistance, Dr. Dirk Jan Stenvers and his collaborators investigated the effect such "clocks" have on our biology and health.
The circadian timing system consists of a central brain clock in a part of your brain called the hypothalamic suprachiasmatic nucleus, as well as in various peripheral tissue clocks.
The circadian timing system is responsible for the coordination of many daily processes, including the daily rhythm in human glucose metabolism. The central clock regulates food intake, energy expenditure and whole-body insulin sensitivity, which are fine-tuned by local peripheral clocks.
For instance, the peripheral clock in the gut regulates glucose absorption, peripheral clocks in muscle, adipose tissue and liver regulate local insulin sensitivity, and the peripheral clock in the pancreas regulates insulin secretion.
Misalignment between different components of the circadian timing system and daily rhythms of sleep–wake behavior or food intake as a result of genetic, environmental or behavioral factors might be an important contributor to the development of insulin resistance. Specifically, clock gene mutations, exposure to artificial light–dark cycles, disturbed sleep, shift work and social jet lag are factors that might contribute to circadian disruption.
The point of all of this clock business is that food timing matters. As the Professor of Regulatory Biology Laboratory at the Salk Institute, Dr. Satchin Panda puts it:
"When you eat is more important than what you eat."
Key endocrine functions such as insulin secretion and insulin sensitivity appear to be optimal in the morning, suggesting that concentrating food intake within the earlier daylight hours is superior for circadian alignment.
Which is what the second research scientist I mentioned above, Nimet Maherali, PhD, discovered in her work, as you'll learn about next.
To Reverse Prediabetes, Stop Eating Earlier
In her first-hand account, Dr. Nimet Maherali - who has studied diabetes at Harvard University and is developing a therapy for type 2 diabetes. - describes how she had more to learn about controlling and even reversing this disease through a Time Restricted Eating (TRE) approach.
She had great motivation for this work - she found out that she's prediabetic!
It happened to Dr. Maherali like it does to most of us whose harried, unquestioned lifestyle leads to insulin insensitivity and prediabetic blood glucose numbers. She gradually became overweight and ate whenever she could as she strenuously applied himself to her profession.
Dr. Maherali TRE Protocol
Once she was diagnosed as prediabetic, Dr. Maherali became determined to improve her blood glucose numbers and insulin sensitivity. She remembered the name of a researcher, Satchin Panda, whose research showed that the timing of food intake has important consequences for metabolic health.
Two studies on this caught her attention:
- Mice given food during active/waking hours are metabolically healthier compared to mice given food during sleeping hours. 
- Mice exposed to food for 8 hours a day versus 24 hours a day are protected from obesity and metabolic disease, despite consuming the same number of calories. 
It wasn't clear to her whether this protocol could be applied to reversing insulin resistance in humans, but the underlying mechanism made sense, and it seemed worth trying. She decided to limit his food intake to an 8-hour window each day, with no change in food type or quantity.
Dr. Maherali didn't specify when her feeding window began each day, but said it ended at 8:00 PM; the math then suggests she began eating at noon. In three days her fasting blood glucose levels to return to normal, but her average glucose test — the HbA1c — remained at the prediabetic level of 6.1%
Nervous, she contacted Dr. Satchin, who suggested to two things:
- Further cut the feeding window from eight hours (12:00 PM to 8:00 PM) to six or seven hours, and
- Eat oats and lentils to help with the longer fasting times, given that they're both satiating.
Dr. Maherali did change her TRE plan, but not by reducing the feeding window to under eight hours. What she did is to do all his eating earlier in the day, between 10:30 AM and 6:30 PM. In addition, she restricted all refined carbohydrates – no added sugar, no bread, no potatoes, no pasta, no rice, no processed fruit juice.
Her TRE Challenges
Dr. Maherali faced two challenges on his TRE program:
- Eating enough food during the given time window. She addressed this being mindful that she not become so distracted by work and the events of his life that he didn't eat enough during her feeding window.
- Being ravenous during the second week on TRE. She dealt with this by drinking water and after six weeks, became accustomed to the protocol.
Her Health Improvements from TRE
After two months on TRE with no refined carbohydrates:
- Weight loss of 13 pounds, and
- A loss of two inches around the lower waist (belly) – an area that was before intractable to his weight loss efforts.
After six months on TRE:
- HbA1c was one percentage point lower – from 6.1% to 5.1% – she's longer pre-diabetic.
After eight months on TRE:
- From the two month mark on, she became less restrictive about food choices, including the reintroduction of some refined carbs, without gaining weight. and was able to enjoy a full range of holiday foods.
- She lost 20 pounds, or 12% of his starting body weight.
- She lost four inches around the waistline.
Dr. Maherali's Overall TRE Assessment
- It provides one clear rule he can follow — eat within a specific time window.
- It worked for her friend who lost 28 pounds in four months, about 13% of body weight, using a fasting time of ~14 hours per night. This person did not overtly restrict food types (aside from eliminating 1-2 sodas per week), and did not feel deprived on this diet.
- It improved her sleep quality, skin, and heart rate (lower pulse).
- When we eat has profound implications for health, independent of food type or quantity, although quality macronutrients (protein, carbs, fats) will amplify better health outcomes.
What you now have is a map that will lead you to lower blood sugar, a particularly worthy goal should you need to reverse prediabetes, or even type 2 diabetes. In addition to TRE, there are also a few supplements that may help.
You can improve many biomarkers for health, and potentially reverse diabetes, by doing just three things:
- Reducing the time span within which you eat to less than 12 hours; and
- Stop all eating and drinking (except water) by 7:00 PM or earlier, which will best align you with your circadian rhythms.
- Give yourself a relief valve; meaning, when you feel you need a break, return to your comfort zone rather than abandon the time restricted eating (TRE) protocol entirely.
If you want to reverse prediabetes, I strongly recommend that you give TRE a whirl, but approach it slowly. Try reducing your feeding window by only 1/2 hour each week, and pushing back the last hour you eat at night by 1/2 hour each week as well.
And know that there's no way to get around feeling hungry at first. You'll have to become accustomed to that feeling without panicking. Try drinking purified water. If that doesn't help, add some cold pressed organic apple cider vinegar to the water or herbal tea. Eventually, exclude it so that you're only drinking water.
One last word on the matter is to recruit a friend, or better yet, whomever you live and eat with. It's very helpful to have someone to lean on when you seek to change something so ingrained as when you eat, because change is hard.