The Theory

Your metabolic system is adaptive. If your diet’s mainly starchy carbs, then it gets used to using those as your main energy source. And although your body is capable of generating glucose from other sources, it doesn’t have to, so it stops. Ditch the carbs for long enough and, if you’re eating plenty of protein and fat, your body will start converting them for energy instead, making you a more efficient fat-burning machine. You’ll also cut down on insulin spikes and (hopefully) cravings.

The Evidence

It’s pretty solid. In a meta-analysis of 17 different clinical trials, low-carb diets beat low-fat diets for both weight reduction and a lowered risk of cardiovascular disease. There’s even some evidence that low-carb diets can halt – or reverse – the onset of type 2 diabetes.

The Good

Apart from all of the above, some research indicates that molecules known as ketone bodies, which are generated by very low-carb diets, can slow some of the effects of ageing. It’s also fairly adaptable: many nutritionists suggest timing carb consumption around workout days (and specifically before or after workouts), helping out when fast energy’s needed.

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The Bad

In the early going, at least, low-carb is tricky to stick to, as your body initially refuses to adapt and demands sources of fast energy. There’s also expense to factor in – in most of the developed world, grain production is heavily government-subsidised, which is partly why foods full of starchy carbs are cheaper than protein and fat-rich foods.

Eat More Of These

Cutting carbs generally means that you will need to increase your intake of another food group to make up for the reduced calories. This is usually protein or fat depending on which low-carb plan you opt to follow. Another common move is to replace your carb-heavy foods with vegetable alternatives, like courgette spaghetti or cauliflower rice.

Avoid These

Sugar and starchy carbs like bread, potatoes, pasta and rice are the first to go on a low-carb diet. If you are being especially strict about the diet the aim is to cut grains and starchy foods out altogether, and avoid sugar where possible, although it’s very tricky to go completely sugar-free. Less strict versions of a low-carb will allow small portions of starchy carbs, usually timed around exercise.

The Expert Verdict

Going low-carb can provide a quick fix, but dietitian Chloe Miles of the British Dietetic Association has reservations about the diet’s long-term appeal. “Low-carbohydrate diets do seem to result in rapid weight loss in the short term, but in the long term they are thought to be no more effective than a traditional reduced-calorie diet. If your carbohydrate intake is very low you may also miss out on important nutrients such as fibre, which is important for a healthy gut.”

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Low-Carb Meal Plan

To aid your fat loss efforts, follow this seven-day low-carb meal plan and easy-to-follow tips from trainer Rich Phillipps.

Day One

Breakfast: Scrambled eggs with wilted spinach; apple

Lunch: Chicken and red pepper wrap with spicy mayonnaise, carrot sticks and hummus

Dinner: Salmon fillet, baked sweet potato and roasted broccoli

Snack: Whey protein shake; pear

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Day Two

Breakfast: Full-fat yogurt with cashew nuts and banana

Lunch: Chicken, avocado, cucumber, tomato and radish salad with balsamic vinegar dressing

Dinner: Beef and onion bolognese with courgette linguini

Snack: Protein bar/shake

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Day Three

Breakfast: Omelette made with onions and mushrooms

Lunch: Chicken, mango, cucumber and tomato salad with balsamic vinegar and olive oil dressing

Dinner: Free-range sausages with mashed sweet potato and green beans

Snack: Yogurt with fresh berries

Day Four

Breakfast: Egg fried in coconut oil served with almonds and strawberries on the side

Lunch: Free-range sausages, vegetable sticks and hummus; banana

Dinner: Turkey burgers with salad and sweet potato chips

Snack: Apple; protein shake

Day Five

Breakfast: Poached eggs with wilted spinach and granary toast

Lunch: Spicy chicken and salad wrap; fruit salad with full-fat yogurt and desiccated coconut

Dinner: Beef chilli made with onions and peppers (make a double portion), rice

Snack: Protein shake; handful of brazil nuts

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Day Six

Breakfast: Poached eggs, ham, granary toast and fried tomatoes

Lunch: Leftover beef chilli

Dinner: Baked haddock, mixed roasted vegetables and new potatoes

Snack: Protein shake

Day Seven

Breakfast: Scrambled eggs with paprika and lime, wilted spinach and mushrooms

Lunch: Chicken breast slices with beetroot and mixed nuts; apple

Dinner: Roast chicken and sweet potatoes and roasted broccoli

Snack: Frozen mixed berry smoothie with strawberry whey protein

Low-Carb Diet Tips

Stick with it

“Initially you may experience slight brain fog, sweet cravings and mild headaches as your body starts to shift to a more effective state of fat-burning,” Phillipps says. “This experience is different for everyone, but stick with it as it will soon pass – and it’ll be well worth it in the long run.”

Eat more protein

“You want to burn fat, not lose existing muscle mass. But with relatively few carbs to support your workout recovery, eating protein with every meal becomes essential. Red meat, poultry, fish and eggs are all ideal options.”

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Go green

“A common complaint with low-carb diets is constipation, which is normally a side effect of not eating enough fibrous vegetables. Be sure to include at least one or two handfuls of the green stuff in each meal to avoid this – think broccoli, asparagus and kale. This will also keep your digestive system healthy and help keep you full.”

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Feast on fat

“A mistake often made with low-carb diets is not eating sufficient fats and ending up on a low-carb/low-calorie diet. This is a disaster and at the very least will make the diet almost impossible to stick to. To avoid this, cook with butter or olive oil and snack on nuts, which provide essential fatty acids to to replace the calories you’re missing out on due to the lack of carbs.”

Add a refuel day

“Try to maintain a very low carb intake (or ideally cut them out altogether) for a fortnight, then you can begin to reintroduce one high-carb ‘refuel’ day per week. This will allow you to replenish your glycogen stores and ensure that your thyroid does’t become sluggish – which would affect your metabolism, resulting in a negative impact on fat loss – thanks to constant low-carb eating. For optimum results, stick to clean carb sources such as oats, sweet potatoes and brown or wholemeal rice.”

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The No Sugar, No Starch Diet

Still not sure how to get started with low-carb eating? For a slightly simpler (and more beginner-friendly) approach, try the No Sugar, No Starch diet – as recommended by the Duke University Medical Centre’s Lifestyle Medicine Clinic – which offers simple guidelines on different food groups and how much of each you should eat. Here are the types of food you can have, and which ones to avoid.

Every day

  • At least 170g salad greens (spinach, rocket, lettuce etc)
  • At least 100g non-starchy vegetables (avoid potatoes, basically)

Often

  • Meat and poultry
  • Fish
  • Eggs
  • Vegetables (apart from potatoes)

Limited quantities

  • Cheese
  • Fruit
  • Potatoes

Snacks

  • Hard-boiled eggs 
  • Nuts
  • Carrot and celery sticks with houmous
  • Cottage cheese
  • Beef jerky (with no added sugar)
  • Olives
  • Avocado

What to avoid

  • Bread and other foods containing flour (eg cakes)
  • Sugar
  • Cereal
  • Fruit juices
  • Honey
  • Canned soups
  • Ketchup, sweet condiments and relishes
  • Alcohol
  • “Fat-free” or “light” products and foods, which often contain hidden sugars and starches
  • Artificial sweeteners
  • Fizzy drinks
  • Pretty much all processed foods

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