Time restricted eating for health

time restricted eating image with clock and food

Time restricted eating for health clearly falls under the Nutrition pillar of Lifestyle Medicine. But what is Time Restricted Eating (TRE)? Does it really benefit health? And how?

What is time restricted eating?

TRE basically means what it says. You only eat within a narrower time-frame than normal. Typically this is cited as an 8 hour window. So, perhaps you first eat at 10.30am and finish by 6.30pm. Absolutely nothing with calories passes your lips for the other 16 hours. You may have water and other drinks that carry no calories.

It’s a version of Intermittent Fasting. But often now, many people prefer to separate Intermittent Fasting from TRE. Intermittent Fasting increasingly is viewed as a day-long fast, or longer. Which is done intermittently. TRE is something many people will do every day, or maybe several days each week.

Does time restricted eating benefit your health?

There are certainly studies that have shown people benefit from TRE. Benefits vary from weight-loss, through reductions in “bad” cholesterol, reductions in inflammation, lower blood sugar levels, lower blood pressure, and an increase in autophagy. Autophagy is the process whereby your immune cells attack and remove senescent cells. Senescent (dying) cells are cells that can sometimes turn into cancerous cells. So, removing more senescent cells is widely agreed to be a good thing.

How does it benefit health?

I’m going to largely duck this question. Read the review I have linked to above. Because there are a number of proposed mechanisms and those mechanisms are complicated. However, a relevant point worth making is why TRE might be beneficial. The obvious one to spot is that it’s easier to eat fewer calories. If you’re only eating within and 8 hour window – and probably only eating 2 meals a day – you will almost certainly consume fewer calories. Definitely helpful if you’re trying to lose weight.

Honouring our evolution

For most of human history – approximately 3 million years – food was often hard to come by. Humans often fasted. They probably swung between times when they had plenty of food, and times when there simply wasn’t enough. Fasting was a big part of life.

Of course, that doesn’t necessarily mean that fasting – or going without food – is good for us. But look at it another way. Nature operates in cycles. This is obvious when we consider the seasons. And it’s obvious when you think about day and night.

There are cycles. This is nature’s normal.

Your digestive tract needs downtime. If you spend most of your day (and evenings) grazing/eating, you are not giving your digestive tract that rest.

It would make sense that there are health benefits to having fasts that amount to more than 8-10 hours.

What are other factors you could consider along with time restricted eating for health?

Exercise

Exercising in a fasted state has other benefits. It helps you to become metabolically flexible. This means you can get your energy from glucose or fatty acids. People with diabetes and obesity have poor metabolic flexibility. If you are someone who feels faint just before your regular meal times and you’re desperate to eat, you may well be metaboicaly inflexible. This could indicate an increased risk of diabetes and other metabolic disorders.

If you’re wondering what the signs of metabolic inflexibility are, here they are:

Fluctuating blood sugar levels

Insatiable hunger

Poor quality sleep

Depression

Fatigue

  • Inability to exercise when you’re fasted i.e. you can’t exercise in the morning before breakfast

Sound familiar? It might be worth getting your fasting blood sugar checked.

On a personal note, I only practise time restricted feeding in this way once a week. On a Wednesday I will stop eating around 3pm and not eat again until 7am the next day.

For many many years I have cycled for nearly an hour first thing in the morning in a fasted state. I’m convinced this helps me maintain metabolic flexibility. I don’t have energy dips. I am very rarely hungry in the mornings. In fact, I could easily skip breakfast every day. I don’t, because I cycle 26 miles, 4 days a week and so I need the calories!

I’ve also started once a month fasting for 24 hours. So long as you keep busy, I find it’s not that hard. Though sometimes it is!!

Have a go, and let me know how you get on…

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