Is Time-restricted Diet really safe for people with type 2 diabetes?

The prevalence of type 2 diabetes increases with the increasing incidence of obesity, and as a measure of excessive obesity, high body mass index (BMI) is a major risk factor
for the development of type 2 diabetes.
Both the American Diabetes Association (ADA) and the European Association for the Study of Diabetes (EASD) recommend lifestyle changes as the first step
in preventing and treating type 2 diabetes.
However, it is difficult for patients to adhere to and maintain weight loss
in the long term in clinical practice.

Today, the most common weight loss strategy for people is to limit calories in their diet
.
This method is effective, however, many people find it difficult to stick to this dieting style
.
Another option is intermittent fasting, which can be divided into different categories, one of which is time-restricted eating (TRE), which is considered a viable and effective lifestyle intervention and has recently become increasingly popular because of its simple nature and without restrictions
in caloric intake and dietary composition.

Recent studies have shown that TRE can lead to weight loss, improved insulin sensitivity and glucose tolerance in people at high risk of overweight and type 2 diabetes
.
This suggests that TRE may be a promising approach, but a major concern is the risk
of hypoglycemia that may occur when patients are concomitantly treated with hypoglycemic drugs.
Therefore, a more thorough assessment
of drug safety is needed before intermittent fasting is recommended for patients with type 2 diabetes.

In a crossover study, Kahleova et al.
investigated the effects of six meals a day (breakfast, lunch, dinner and three snacks) versus two meals a day (breakfast: 6-10 a.
m.
, lunch: 12-4 p.
m.
) on body weight, liver fat content, insulin resistance and β cell function, under the same calorie restriction (500 kcal per day
).
The study suggests that for people with type 2 diabetes, eating two meals a day may be more beneficial
than eating six meals a day.
The study did not investigate primary results of safety or tolerability, nor did it report specific meal times
.
Participants were asked to continue their anti-diabetic medication regimen unless they had recurrent hypoglycemia
.

The data showed that metformin was the most commonly used anti-diabetic drug, with more than 30 patients per 1,000 patients
.
Insulin is the second most commonly used drug, with a slight increase
in use over the past few years.
The use of sulfonylureas has decreased, while the use of GLP-1-RAs and SGLT-2 inhibitors has increased
.
The use of DPP-4 inhibitors has been stable over the past few years, with α-glucosidase inhibitors, thiazolidinedione and other hypoglycemic drugs in the A10BX group being used at low or absent
levels in Denmark.

The number of people using different antidiabetic drugs per 1,000 inhabitants in Denmark in 2010

Since sulfonylureas carry the risk of hypoglycemia, caution should be exercised when used in combination with TRE, it is recommended to take sulfonylureas 30 minutes before meals, since food can reduce their absorption
in the intestine.
Different sulfonylureas have different doses, and their absorption rates, elimination pathways, and binding sites to target receptors are also different
.

Not all ongoing or planned studies included safety-related outcomes, and these studies varied
widely in terms of inclusion and exclusion criteria for drug types.
Some medications given to participants may not cause a big problem with hypoglycemia risk, but other potential safety concerns should be considered
.
The main side effects of metformin are related to the gastrointestinal tract, so metformin should be taken with food, twice
daily.
Due to the short interval between taking metformin, eating times for a few hours may or may not be a problem
.

In conclusion, it may be safe
for people with type 2 diabetes to receive the TRE regimen.
However, further investigation and larger studies over a longer period of time
are needed to make definitive recommendations on the safety of TRE for type 2 diabetes.

References: Uldal S, Clemmensen KKB, Persson F, et al.
Is Time-Restricted Eating Safe in the Treatment of Type 2 Diabetes?-A Review of Intervention Studies.
Nutrients.
2022 May 30; 14(11):2299.
doi: 10.
3390/nu14112299.
PMID: 35684097; PMCID: PMC9182892.