Rockpool Publishing

Metabolic Clock - Womens health and fitness

In her new book, The Metabolic Clock Cookbook, Julie Rennie recommends treating your metabolism “like a miniature sun”. She says that your body wakes up gearing up for the day ahead and hits its stride at noon. Then it settles down in the evening to rest up before another big day.

A 2009 study by University of California Irvine researchers discovered that circadian rhythms regulate the energy levels in the body’s cells. Scientists found that the biological clock controls enzymes in a cellular structure called the mitochondrion. This cell structure is dedicated to energy metabolism. What’s really interesting (stay with us while we get all nerdy on you) is that the biological clock controls these enzymes through acetylation of proteins. This is where your genes are switched on and off in cells based on how much energy you’re clocking up. Okay, time to dial up the nerd metre again (it’s for your own good – promise). The most significant acetylation processes are actually controlled by a protein called SIRT1, which works as a sensor for how much energy is in the cell. The response of SIRT1 is directly influenced by how many nutrients a cell is consuming. What all this means is that not only are the bodys’ day-night patterns (circadian rhythms) and metabolism linked, they depend on each other.

It’s important to understand all this if you want to age more gracefully than Joan Rivers, because SIRT1 modulates your metabolism and how you’re ageing. A pattern of lazy, late meals means you’re eating at the slowest stage of the metabolic cycle and your body has to work harder to “digest the food and you may wake up feeling very sluggish and tired”. This will speed up your metabolism and “burn body fat for fuel while making it easy to shed excess kilos”.



It’s common knowledge that breakfast is the most important meal of the day. But there’s an extra way to boost your metabolism before you pour the milk into your cereal bowl. “You have been fasting throughout the night, so a cleansing drink will help clear out the toxins and rehydrate your digestive system. Enzymes from raw food ingredients will kick-start your metabolism.”



1 stick celery

1 carrot

1⁄4 small beetroot (beet)

Small slice of ginger

1 green apple, cut into


3 kale leaves (Tuscan cabbage)


Juice all ingredients in a juice extractor and drink immediately. The enzymes begin to oxidise as soon as you juice, so it doesn’t store well.



“Eating breakfast cranks up the digestive furnace and gets your metabolism moving. An early breakfast will provide fuel for the day’s activities,” says Rennie. Don’t worry, boosting your metabolism and losing weight doesn’t mean your brekkie needs to have a postcode in Bland City. You can enjoy mouthwatering meals like this special occasion recipe that will give you the energy you need to start the day.


Time’s a tickin’ and it’s been a few hours since you gave your tum a good feed. Rennie recommends eating fruit at around 10am. She says, “the fibre and water content in the fruit will create the right variables for digestive vitality. Make sure you include lots of variety for the antioxidants and trace minerals.” And if you’re not feeling full as a bull after the fruit, that’s actually a good thing, says Rennie. “If you are hungry after eating fruit mid-morning, this means that your metabolism is speeding up and you can look forward to enjoying  your midday meal”.


There’s nothing better than devouring a lunch packed with mouth-watering flavour. These metabolism-boosting rice paper rolls will satisfy not only your taste buds, but your body clock too. Rennie recommends eating a nourishing meal “close to midday when your metabolism is most active. This will provide you with the fuel for an energetic afternoon.”

Hannah Blamey – 05 January, 2013