11 Benefits of Time-Restricted Eating
Life is busy. You get up early to work, to get the kids off to school, or to hit the gym (or for many in midlie… all three!).
Your days run long, dinner is often later than you intended and before you know it, it’s well into the night.
The blurring of the lines between work and home life with more people working remotely, alongside our constantly connected society, has more people eating later in the evening.
Today more than 40% of all the calories we consume come after 6 pm.(1)
Why does this matter? A growing body of research shows eating over a prolonged period each day or eating more than three meals a day is increasingly common and associated with obesity, type-2 diabetes, metabolic syndrome, and cardiovascular disease. (2-12)
Our modern work and food environment are leading to us significantly over fuel throughout the day. In America over 50% of the population eat for more than 15 hours a day and only 10% of adults eat for less than 12 hours a day. (3,5,6)
This prolonged eating window (i.e. eating for more than 12 hours per day) is so detrimental to your health, it’s been identified as one of the most prominent modifiable risk factors – alongside obesity and physical inactivity - contributing to poor metabolic and heart health. (13,14)
The good news is, making small improvements in your diet and lifestyle are the most powerful tools to reversing these trends. (13-15) Let’s explore.
Time-Restricted Eating: What Is It?
Time-restricted eating (TRE) is a lifestyle intervention where eating is restricted to a reduced, fixed number of hours in the day (thereby extending your ‘fasting’ period as well). (16) For example, rather than eating your breakfast at 7 am, you delay breakfast until 10 or 11 am, then you stop eating after dinner at 6 or 7 pm, thereby 'restricting' your eating window to approximately 8-hours.
(Many people and media refer to this as intermittent fasting, which is an umbrella term for various meal-timing schedules). How can TRE help to support weight loss, improve blood sugar control, or lower chronic inflammation?
Simply by reducing the hours in the day that you eat.
The Pitfalls of 'Constant' Grazing
You may not realize it, but you may be eating for as long as 16 to 18 hours of the day. Don’t think this applies to you? It’s an easier trap to fall into than you think. For example, you get up early for work and eat breakfast at 6 or 7 am. After a long, busy day you crash on the couch for a late snack or glass of wine at 10 or 11 pm (or for many, even later). In this scenario, you’ve been eating for 16+ hours of the day.
In today's food environment, with calorie-dense (nutrient-poor) foods all around us, it’s incredibly easy to do. That's a massive change to our parent's generation (and certainly grandparents) who operated primarily on the 'three-square meals' approach. (I can still hear my mom yelling, 'No snacking, you'll spoil your dinner!')
The Consequences of 'Over-Fueling'
A new study from Dr. Satchin Panda, Ph.D. - pioneer of the early work on TRE and circadian rhythms - offers a graphic that highlights the pitfalls of eating more than 12 hours of the day. (17)
If you eat for more than 12 hours a day, you significantly increase your risk of:
obesity
heart disease
metabolic disease (like type-2 diabetes)
liver disease
poor sleep
lower quality of life
It’s also been demonstrated that even irregular meal timing has adverse effects on your heart and metabolic health. (5) It may seem trivial, but if you eat at markedly different times each day, it may be setting you up for significant problems down the road.
11 Benefits of Time-Restricted Eating
If you’re struggling with weight gain, high blood sugars or high blood pressure, energy highs and lows, chronic pain, etc. then TRE can yield significant benefit.
In overweight and obese individuals struggling with poor metabolic health, research shows the following benefits; (see the graphic below)
weight loss
reduce body-fat %
reduce abdominal fat
improved fasting glucose (largely due to weight loss)
improve glucose control
reduce triglyceride levels (fats in your blood)
reduced LDL 'bad' cholesterol
reduced blood pressure
reduced inflammation
reduced oxidative stress
improve QOL (quality of life)
It’s important to highlight these benefits are obtained simply from keeping to a 12-hour eating window (aka – what our grandparents did), without having to restrict intake any further. This is a very achievable target for most people.
Moreover, the beauty of TRE is that it doesn't even matter if you're 100% plant-based, paleo, keto, or anything in between; it still yields benefits in overweight and obese individuals.
How TRE Works: Principles vs. Strategies
All diets operate via the same principles. Regardless if you choose to follow a low-carb dietary strategy, a low-fat dietary strategy, TRE, or any other, the principles behind ‘how’ they work are largely the same. Thus, dietary strategies are all just tools.
To achieve long-term success, you need to find the right tool (i.e. dietary strategy) to resolve your problem. (There is no ‘magic’ diet… sadly)
How does time-restricted eating (TRE) exert its benefits? While there are marginal gains to be made with adjusting the ‘timing’ of your food intake, it’s the drop in total energy (aka - calorie) intake that triggers the overwhelming beneficial responses.
This is a REALLY important point.
The calories you consume (or over-consume) are the biggest signal telling your body to 'build' or 'break down'. This is the key principle at work. This is why people struggling with weight gain or poor health see tremendous initial benefits with TRE; it significantly reduces energy intake by shrinking your eating window.
But, over time as your context changes (from obese to overweight, or overweight to your ideal body composition) you'll likely need to adjust your dietary strategy and implement other tools.
Like any dietary strategy, there are benefits and pitfalls. (I’ll cover the pitfalls I see in practice with TRE in a future post.
To Sum Up
In today’s modern environment, we’re eating later in the evening and eating more high-calorie, ultra-processed foods, which can easily (and often unconsciously) become the default option when pressed for time. This makes TRE a very helpful heuristic or simple rule.
Keeping your 'eating window' to a maximum of 12 hours per day limits the likelihood of over-fueling and late-eating (when things often go wrong).
If you're trying to lose weight or improve your health, sticking to a 12-hour eating window is a pretty good place to start.
It looks like our grandparent's generation's simple rule of eating three square meals a day is still a great heuristic in today's modern world.