Juicy Details

By Dr Liz Applegate

Freshly-squeezed fruit and veggie juice is tasty – but does it live up to the hype?

When you squeeze fresh produce, a good amount – though not all – of the nutrients are transferred to the juice. Those made from leafy greens are rich in magnesium, which is crucial for energy metabolism.

A cup of berry, citrus, or kiwi juice provides more than 100 per cent of the Recommended Daily Value (RDV) for vitamin C, an antioxidant that protects muscles during workouts. And a cup of carrot juice has 900 per cent of the RDV for vitamin A in the form of beta-carotene – an orange-yellow pigment that defends the cells of your body against oxidative damage.

Drinking juice cannot flush chemicals, such as pesticides, from your body. In fact, your body does a great job of eliminating any toxins itself. But juice does provide antioxidants that, over time, may help protect against the long-term effects of being exposed to harmful compounds.

Drinking a cup of fruit juice pre- or post-run will hydrate you, while supplying 15 to 40 grams of carbs. But be aware that a single cup can also pack up to 700 kilojoules, which adds up quickly if you’re watching your weight. Vegetable juice typically has fewer kilojoules – 200 to 400 per cup.

Some juicing enthusiasts claim drinking only juice for a few days and not eating will give your digestive tract a needed break. But your stomach, intestines, and colon are muscles that need to work to stay in shape. Without fibre from whole foods, your GI tract may actually become more sluggish on a juice-only diet.

In a recent study, cyclists drank beetroot juice or a placebo for six days. The next day they rode for an hour, and then raced a 10-K time trial. Those who drank beetroot juice rode faster, cycled harder, and used less oxygen during the trial. Researchers credit this athletic boost to the nitrate found in beetroot juice, which indirectly increases blood flow.

Pomegranate and sour cherry juice contain anthocyanidins – antioxidants that help protect muscles. In one study, runners who drank sour cherry juice before a marathon, the day of the race, and after the race had significantly lower markers of inflammation and quicker recovery compared with the placebo group.

Juice-only fasts are touted as a quick way to lose weight. And they are – if you stick to low-kilojoule options (you can down a day’s worth of kilojoules with sugary juices). But juice fasts are far from a healthy or sustainable way to shed kilos. Because juice is low in protein, you’ll lose muscle, hinder tissue repair, and compromise your immunity. Plus, you’ll regain weight as soon as you return to a normal diet.