Every year, a day or two before Yom Kippur, I turn to Google for tips on how to fast.

Not how exactly — that part's simple — just keep my mouth shut; but what I should eat before Kol Nidre, and then the optimum way of breaking the annual abstinence.

This year I’ve thought ahead and asked nutritionist Laura Southern for her top tips so you can concentrate on absolving your sins and not on that banging headache:

Here are Southern’s helpful pointers:

1. Coffee break

The most common cause of a Yom Kippur headache is caffeine withdrawal. Head this off by cutting out or reducing your consumption of coffee, tea and any other caffeinated drinks in the week, or even a few days, before. You’ll be able to  manage the headaches with water and paracetamol. Southern says she has recommended this tip for years and is thanked by people every year for it.

Chia seeds are a superfood worth adding to your diet. Photo: Getty Images

2. Water fill

Another of Southern’s tips is to hydrate fully in the lead-up to the fast. That doesn’t have to involve only drinking a lot of water — although that helps. She advises eating a range of foods that help you increase your water levels. One of her go-tos is chia seeds — a favourite of vegan food writers for making breakfast and dessert pots.

“I’ve been doing a lot of work around hydration this year. Chia seeds have a gel-like coating which gives us really good fibre, and  keeps us full. But also, that gel is basically like a trapped water. The  high fibre means it will sit in your gut slowly releasing water, which is actually really hydrating.”

She recommends having a good helping of chia seeds for breakfast the day before or even finishing your meal with a chia pudding. “That will give you an internal source of hydration — that can reduce the effects of dehydration.”

She says you want a good tablespoon — no more unless you’re used to eating them, as too much can upset your tummy. Since they firm up into a sort of jelly-ish texture, they might work as a parev dessert. Find my recipe for apple and honey chia pudding at here and other recipes online. But be warned:  the texture can be an acquired taste.

Green veggies are a must Photo: Getty Images

3. Go green

Green vegetables are also very hydrating. Southern recommends salad leaves such as rocket, spinach and watercress, which will not only hydrate but fill you with fibre. Cooked greens will also do the job, so serve yourself generous portions of broccoli, cabbage and kale for your pre-fast supper. “They also  provide plenty of trace nutrients and iron, which will give you lots of energy for the fast the next day.”

Ribollita is packed with healthy vegetables and beans

4. Protein positive

Moving on from hydration, another food source to focus on before fasting is protein. “If your evening meal the night before the fast contains lean meat, fish or even beans you’ll feel full for longer.” She advises that a tagine-style dish with chicken or fish, plus beans and vegetables, will not only be satisfying but also help avoid blood-sugar crashes the next day.

“If your blood sugar is stabilised before the fast you should feel better for longer.” Conversely, she advises avoiding foods with high sugar content or highly processed foods, which will make your blood sugar crash, leaving you with that hungover, light-headed feeling associated with low blood sugar.

Limit white carbs - even challah - when you do break fast

She agrees there is nothing more comforting than that first cup of tea and slice of honey cake or challah, but Southern warns it’s not the most nutritious return to eating. “You probably won’t fancy clear broth or green juice, but however you break your fast, listen to your body, and once you’re full then stop. Think: ‘Do I need another four slices of challah and butter before diving into the goujons? Do I need to eat as if I haven’t eaten for a week?”

Her advice is to “stop eating when satisfied and have a healthy breakfast the next day.”

Sweet potato soup Photo: Lisa Roukin

6. Fasting future

Beyond Yom Kippur — once we’ve atoned for our sins — we may want to consider making fasting a part of our lives. Southern says there is now much information and science pointing at fasting as a very positive experience for our health. “The main thing that the studies show is that fasting supports our blood sugar balance — it reduces elevated blood sugar and insulin. If you can get those under control you are then supporting your heart, your cholesterol, your brain health and your weight.”

She explains that every time we eat — even if it’s only cucumbers and carrot sticks — our insulin rises. It is this constant up and down that’s damaging over time. “If you’re constantly eating and getting a bit of a high blood sugar level you can very quickly develop insulin resistance. A 12- or 14-hour fast allows you not to produce insulin and that is what’s helpful.”

She says a regular 12-hour fast can be enough to make a difference and studies show that it seems to work for everyone. “You can have water — that’s totally fine — but doing that regularly is enough to help. It doesn’t have to be every night but if you’re trying to eat within a 12, ten or even eight-hour window five days a week, you’ll probably see a difference within four to six weeks.”

So maybe this can be the new year in which we really start as we mean to go on, making the annual fast the start of something new.

Contact Laura at London Food Therapy