In a study of time-restricted eating, a group of 19 people with metabolic syndrome (also called pre-diabetes) ate their usual meals but ate only between 8AM and 6PM (10 hours) and took in no calories during the other 14 hours each day (Cell Metabolism, Dec 5, 2019). They did not change the amounts or kinds of food that they ate or how much they exercised.
The participants used an app called MyCircadianClock to record everything they ate. After a two-week period where they ate in their normal way and got all of the measurements and blood tests to establish their baselines, they spent three months following the 10-hour time-restricted eating program. At the end of the three months, they:
• had eaten nine percent fewer calories per day (without trying),
• lost three percent of their body fat and reduced their belly fat by three percent,
• lowered their high blood pressure, bad LDL cholesterol, fasting blood sugar, triglycerides, and HBA1c (a measure of cell damage from sugar stuck on cells),
• were able to lower their doses of medications to control their high cholesterol and high blood pressure, and
• slept better at night.
Metabolic Syndrome or Pre-Diabetes
Metabolic syndrome or pre-diabetes affects 30 percent of North American adults. It is diagnosed when a person has three or more of the following:
• obesity (BMI >25)
• high blood pressure (systolic blood pressure >120 at bedtime)
• high bad LDL cholesterol (>100)
• low good HDL cholesterol (<40)
• high triglycerides (>150)
• high HBA1c (>5.7)
• excess belly fat (pinch more than 3″ of fat near the belly button).
Various patterns of intermittent fasting (such as alternate-day modified fasting) have become popular since many people find these diets easier to follow than traditional calorie restriction diets. The type of intermittent fasting used in this study, called time-restricted eating, looks very promising for treatment of patients with metabolic syndrome, pre-diabetes, diabetes or obesity. This new study agrees with the findings of an earlier study that compared eating during a six-hour window (8AM to 2PM) with a program of eating between 8AM to 8PM, or 12 hours a day (Obesity, July 24, 2019).
Reasons to Avoid Having a Fat Belly
Storing fat in your belly, rather than your hips, is associated with diabetes because it means that you probably store fat in your liver. When blood sugar levels rise too high, your pancreas releases insulin, which lowers blood sugar levels by driving sugar from the bloodstream into the liver. Fat in your liver prevents the liver from accepting sugar from the bloodstream to keep blood sugar levels high. Most people with a large belly and small hips have excess liver fat and high blood sugar levels after eating, and are at high risk for diabetes and heart attacks. Intermittent fasting markedly helps to decrease belly fat (Translational Research, October 2014;164(4):302–311).
The authors of these studies agree that calories eaten in the morning count less and are healthier than calories eaten in the evening. Skipping breakfast and lunch has been associated with eating more calories later in the day and significantly increasing the likelihood of developing a fatty liver (Euro Soc of Endoc, 2018 annual meeting in Barcelona, Spain). When you sit around or lie in bed after eating, your muscles will not contract enough to remove sugar from your bloodstream. The best time to eat is before or just after finishing exercising, when your muscles will draw huge amounts of sugar from your bloodstream to help prevent a fatty liver that can cause obesity, diabetes, heart attacks, strokes and premature death.
“Fasting” Programs May Not Be for Everyone
The various types of intermittent fasting can be useful for people who want to lose weight, want to maintain their existing healthful weight, or want to keep from depositing excess fat in their liver. However, some conditions can be worsened or complicated by fasting. Discuss your plans with your doctor, particularly if you are diabetic, have low blood pressure, take medications, or are underweight. You will probably be advised not to use intermittent fasting if you are pregnant, trying to become pregnant, or breast-feeding an infant; if you are under age 14; or if you have a history of eating disorders.
I have used variations of intermittent fasting for several years now, and have recommended them to many others who have been pleased with their success. See Weight Loss with Intermittent Fasting
Why We Use Intermittent Fasting
I am now recommending time-restricted eating (no calories after 6 or 7 PM except on social occasions) to virtually every adult, whether or not they are trying to lose weight, because I feel strongly about not raising your blood sugar just before you go to bed. The results of the study quoted above should be a wake-up call for everyone who has any risk for diabetes, heart attacks or strokes (and that is pretty much all of us.)