The Hazards of the Liquid Diet

Nutrition // 12WBT Staff

In the time it takes to say “grab me a straw” it seems another juice, shake or soup-based diet plan has been released in the market. But replacing meals with liquids is not only unsustainable but potentially dangerous says 12WBT dietitian Georgie Moore.

In the last few years, liquid-based diet plans have emerged as a popular way to expedite weight loss. They encourage dieters to replace regular meals with a liquid alternative in order to shed weight fast. The mass appeal of these weight loss programs is undeniable given the sheer number of celebrity endorsements and television infomercials. But is a bang-for-your-buck approach to nutrition really sustainable? And, for that matter, is it safe?

Nutritionally, the answer is a resounding no. Replacing a balanced, portion-controlled meal with a liquid lunch won’t supply your body with the nutrients it needs. Often, these meal replacements are high in sugar and artificial flavourings while also lacking natural fibre and vitamins, and they may actually cause you to lose muscle – in addition to fat – if they’re low in protein.

The experts are equally unconvinced. 12WBT dietitian Georgie Moore says that if used according to directions, sustained meal replacement may cause the body to “go into ketosis [a dangerous state caused by eating too few carbohydrates that can lead to organ failure] and the user may experience a host of horrendous side effects – nausea, headaches, dizziness, mood swings and gastrointestinal issues.”

And while this may lead to instant results in terms of weight loss, Georgie suggests that the danger lies in lack of education as it’s a bandaid solution to a much more systemic issue. “The user won’t learn anything about eating well, and [ultimately] will still have to consult a dietitian,” she says.

Ironically, the origins of the liquid diet are medicinal. Under the supervision of a doctor, patients undergoing major surgery will traditionally participate in a liquid cleanse one to two days before their operation to clear out any intestinal residue. Side effects of this cleanse often include some weight loss.

And in this capacity, Georgie says that liquid diets still have a purpose. “I would recommend it if I have a client who is morbidly obese and they need to lose weight very quickly for health reasons, like an upcoming surgery,” she says.

But this isn’t to say that meal replacements should be avoided at all costs all the time. “Often people use meal replacements in place of just one meal on occasion,” Georgie says. “This is fine if they’re running late and there’s absolutely no better option. However, it’s not [an attractive option] as an everyday, regular meal choice.”

Part of the reason for this is that liquid meal replacements are known to slow the user’s metabolism, resulting in sluggishness and fatigue. This, in turn, makes it more difficult to exercise and to keep the weight off. Ultimately, the short-term payoff is unsustainable in the long run.

Georgie believes that the best course of action remains portion control, regular exercise and a healthy diet. “You’ll be able to control your health and wellbeing much more than any food replacement will enable you to do,” she says.

The bottom line is that you can’t drink your way to sustained weight loss and if you’re thinking about taking on a liquid diet it’s wise to consult a dietitian first.


It takes consistency and a sustained approach to improve your health and fitness, join the 12 Week Body Transformation and get the tools to change your lifestyle for life and not just a few weeks!