The dietitian's five best diets to focus on in 2021 (and three to avoid at all costs)

• 100 of the best low-carb recipes
• 50 easy vegan recipes everyone will love

The past year has certainly been an interesting one and, from a dietary perspective, things have not been all bad. More time at home has meant that many of us have been able to commit a lot more time and energy to food preparation and healthy eating, which is only a good thing.

Interest in plant-based eating continues to grow exponentially, with a growing number of plant and nut milks a routine part of coffee orders. More than ever, you can find zero-alcohol wines and beers, along with lower calorie alcoholic water and wine spritzers, some of which are quickly taking the place of our favourite wine or spirit. And the snack food section of supermarkets continues to expand, with more products boasting nutritional claims of less sugar, more protein and fewer 'bad' fats.

It is not all good news, though, with a growing habit for ordering our meals straight to our door, as well as desserts and alcohol, resulting in plenty of fat and calories sneaking into our diets each week. With this has come a few extra kilograms, collectively blamed on COVID, although it's almost two years since the pandemic began.

At the start of a shiny new year, before you spend money on yet another diet program that promises that you will look like a supermodel before the end of January, here are the diets that are scientifically proven give you the health- and weight-related results you are hoping for, as well as a few diets to avoid.

1. Lower Carb Diets

Lower carb or moderate carb diets contain 30-40 per cent carbs, generally with a taper at night. Programs such as the CSIRO Total Wellbeing Diet follow this formula. It is an effective, sustainable way to shift half a kilo each week whilst still enjoying some fruit, bread and grains in your eating plan. How to make Adam Liaw's greens and egg salad, pictured.

2. The Mediterranean Diet

Whilst it is not specifically known for weight loss, when it comes to health outcomes, you cannot go past the Mediterranean Diet. The simple formula involves plenty of fresh fruit and vegetables, lashings of extra virgin olive oil, nuts, seeds, fish and little to no processed food, and it is the recipe for a healthy heart and long life.

3. The 5:2 or Fasting Diets

Fasting diets have been shown to help kickstart a number of the body's hormones, including those that regulate fat metabolism. The 5:2 diet involves two low-calorie days each week, while for the 16:8 diet you consume all of your calories within an 8-hour window and then fast for 16 hours. While you won't lose 1-2kg a week using fasting, if you can consistently follow one of the regimes you can lose a couple of kilograms a month without overly strict dieting.

4. Very Low-Calorie Diets (VLCDs)

Not for everyone, Very Low-Calorie Diets contain roughly 800 calories and are often sold as a program in which all meals are replaced by formulated dietary shakes, bars or soups for a period of time. When followed, VLCDs can be extremely effective in supporting relatively quick weight loss of 1-2.5kg a week and are especially effective for those with Type 2 diabetes. For less intense weight loss, followers can replace just one to two meals each day to support calorie control.

5. Vegan

A vegan diet, unlike a vegetarian diet, includes no animal foods whatsoever meaning that the diet is based around legumes, grains, seeds, nuts, fruits and vegetables. While these foods are all exceptionally healthy and mostly lower in calories than diets that include animal-based protein, vegan diets are not necessarily lower in calories than other diets, meaning they will only result in weight loss if they are also calorie controlled. How to make Adam Liaw's Piyaz salad and Andrew McConnell's tomato and chickpea curry.

The diets to avoid at all costs:

Lemon detox diet

Basically, this is a starvation diet. Deficient in all the key nutrients and even dangerous for those with hormonal conditions such as insulin resistance and diabetes, there is nothing positive that can be said for this diet, especially since you are likely to regain most, if not all, the weight you lost once you start to eat again.

Juice fasts

Often referred to as a 'cleanse', a juice diet works in a similar way to the lemon detox diet but with slightly more sugar and calories. Long-term juice diets are deficient in protein, fats, vitamins and minerals and, again, any weight you lose is likely to be regained once you start eating again.

Alkaline diet

The alkaline diet suggests that alkalising foods (those with minimal acid-forming properties) help to restore the body to an alkaline state. It is believed by followers that an alkaline body is the key to new cell generation and disease prevention. While this may sound fantastic, the reality is that the pH of the body is largely out of our control which means the alkaline diet cannot do what it says it does.

Seven easy ways you can have a healthier 2022:

• Play the long game. All diets work if you can follow them, long-term. Seek out sustainable options if your goal is weight loss in 2022.
• Focus on vegetables. The easiest way to improve your nutrition and support weight control is by doubling your daily vegetable intake to 7-10 serves each day.
• Check your sugar intake. It is recommended adults consume no more than 5-6 teaspoons of added sugar or less than 25 grams each day. Check food labels and look for foods with less than 5 grams of sugars per serve.
• Plan your meals in advance. Planning is the key to dietary success. Each week, set aside a few minutes to plan a few meals and organise your shopping list so you have the ingredients on hand that you need to eat well.
• Limit your takeaway. Fast food and takeaway meals contain up to double the calories of meals you prepare at home. Limiting these high calorie choices to at most once each week will go a long way in improving your nutrition.
• Reduce processed snacks. We all snack a lot more than we need to. Focusing on wholefood snacks like nuts, yoghurt, cheese, fruit and vegetables is an easy way to keep your calorie intake controlled.
• Seek out wholegrains. Carbs are not bad if you choose the right ones. Make wholegrain breads, cereals and crackers the staples you keep at home.

Susie Burrell is a dietitian.