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Slow-carb diet: What is it and does it work for weight loss?

Learn more about this high-protein, low-carb diet.

Does the Slow-Carb Diet Work for Weight Loss? | Juniper

Heard of the slow-carb diet but wondering exactly what it entails and why your carbohydrates should stay sluggish?

Designed by author, podcaster, and lifestyle guide Tim Ferriss — also the guy behind books like The 4-Hour Body and The 4-Hour Workweek — the slow-carb diet is a high-protein, low-carb diet that has reasonably strict guidelines on what foods you can eat and on which days you can eat those foods.

Curious? Let’s find out more.

What is the slow-carb diet?

The point of the slow-carb diet is to promote fat loss and improve health, not through restricting calorie intake but through restricting the foods you eat.

Its basic premise is that by eating only a few specific food groups and curbing the consumption of others, you can boost your metabolism, regulate your blood sugar levels, gain energy, and lose weight.

The slow-carb diet suggests you only eat a mix of proteins, legumes, veg, fats, and spices while avoiding carbs, sugar (including fruit), and liquid calories.

In other words, it prioritises low glycemic index (GI) foods that release energy slowly — hence the 'slow' part of the name.

But, the diet also includes a ‘cheat day’ once a week when you can eat and drink whatever you want.

This not only gives you a break but also prevents cravings and your metabolism from slowing down. The cheat day is what differentiates the slow-carb diet from other low-carb eating plans — like keto, paleo, or Atkins. 

The rules of the slow-carb diet

The slow-carb diet is intended to be super simple and fairly restrictive, making it easier for dieters to stick to. Ferriss argues that the more options someone has, the more likely they are to stray. 

The regimen is based on 5 basic rules to abide by if you're hoping to lose weight. These are:

1. Steer clear of carbs

On the 6 diet days, you need to avoid almost any kind of carb: think bread, pasta, rice, flour (including baked goods that are made from it), breakfast cereals, potatoes, fried foods coated with batter, or crumbs.

And while the focus is on avoiding white or processed carbohydrates, whole grains and brown carbs, like brown bread, brown rice and wholemeal flour, are also off the table.

2. Stick to the same meals

In place of refined carbs, Ferriss recommends eating from 5 primary food groups: animal protein, certain vegetables, legumes, fats, and spices/seasonings.

He also encourages eating as many proteins, veg and legumes as you want, and lower amounts of fats and spices.

Within those food groups, you’re able to combine different foods to create a small range of easy meals that you can replicate again and again.

The idea behind repeating the same few meals is that it keeps things simple and helps dieters maintain their regimen.

The diet also advises eating only 4 meals a day and avoiding snacks.

3. Don't eat fruit

Like many other low or no-carb diets, the slow-carb eating plan recommends eating absolutely no fruit.

The thought is that the fructose in fruit hampers weight loss efforts because it can trigger the hormones that lead to weight gain. 

The only fruits allowed are tomatoes and avocados (yep, they’re technically fruits, not veg!). But, ideally, you should only eat each in moderation.

(It’s worth mentioning here that there’s limited evidence eating fruit can promote fat storage. There are studies linking fructose and body weight, but in those studies, participants typically consumed much higher quantities of the stuff than is found in fruit [1][2]. Instead, researchers have found that fruit can actually help with weight loss [3].)

4. Avoid liquid calories

Beyond what you eat, the diet has reasonably strict rules around what you drink.

To avoid consuming excess calories that offer little to no nutritional benefit (aka empty calories), don't drink calories. Instead, Ferriss suggests sticking to zero-calorie drinks like water, unsweetened tea or coffee (with no added milk), and other drinks that are completely devoid of calories.

That means no juices, fizzy drinks, and milk (including non-dairy). However, you can have a glass of wine each night, preferably a dry one, even on diet days.

5. Have a cheat day

Your reward for adhering to 6 days of minimal carbs, lots of protein and no fruit? One day per week where you can eat and drink whatever your heart (and belly) desires.

This could be a cheeky white-bread sandwich or a chippy tea, but it could also be a full-on, calorie-laden blowout.

The diet argues that this day is a must because it resets your metabolism and prevents you from binge eating the rest of the week.

What foods can and can't you eat?

The diet recommends 5 main food groups, but what do those food groups contain? Here’s what you can (and can’t) eat on the slow-carb diet.

Slow-carb foods you can eat

Animal proteins


  • Lentils
  • Black beans
  • Pinto beans
  • Red kidney beans
  • Soybeans
  • Chickpeas (restricted amounts, as these are higher in carbs)


  • Spinach
  • Broccoli
  • Cauliflower
  • Asparagus
  • Green beans
  • Brussels sprouts
  • Kale
  • Tomatoes
  • Bell peppers
  • Cabbage


Spices and seasonings

  • Salt and pepper
  • Hot sauce
  • All spices and herbs
  • Mustard
  • Vinegar
  • Lemon and lime juice


  • Water
  • Unsweetened tea and coffee (without milk or sugar)
  • No-calorie drinks

Foods you can’t


  • Bread
  • Rice
  • Pasta
  • Potatoes
  • Cereal
  • Tortillas
  • Quinoa, oats, and other whole grains

Sugary foods and drinks

  • Fruit (all types, except tomatoes and avocados in moderation)
  • Fruit juices
  • Fizzy drinks (regular and diet)
  • Sweets
  • Biscuits
  • Cakes
  • Pastries
  • Ice cream
  • Sugary snacks


Processed foods

  • Packaged snacks (crisps and crackers)
  • Fried foods (especially with batter)
  • Fast food
  • Processed meats (sausages, hot dogs, and bacon)


  • Alcohol (especially beer and sugary cocktails)
  • Sweetened coffee drinks
  • Milk-based beverages

Fats and oils

  • Margarine
  • Vegetable oils
  • Butter (in excess)

Does the slow-carb diet work for weight loss?

As far as weight loss goes, the slow-carb diet has a few things going for it and a few things working against it.

First up, avoiding certain types of carbs — namely the processed ones — does have some merit.

These carbs have been stripped of much of the good stuff, like fibre and several important nutrients, which means they can cause blood sugar spikes and weight gain [4][5].

The same goes for eliminating sugary drinks and foods from your diet — these are also linked to higher fat stores [6][7].

Plus, consuming more protein could also aid weight loss [8]. Protein helps to build lean muscle, boosts your metabolism, and influences the hormones that control hunger and satiety. All of this can contribute to losing weight.

On the flip side, though, the diet promotes the concept that all carbs should be avoided.

Contrary to this idea, there’s evidence that including more whole grains and other fibre-rich carbs in your diet could actually promote weight loss [9]. This is because fibre slows down digestion and makes you feel fuller, potentially reducing the urge to overeat.

As well, the lack of variety may be challenging for some to stick to.

Mostly eating animal proteins and veg, and no fruit, dairy or whole grains, may create meal monotony, which could cause dieters to deviate. While the slow-carb cheat day is intended to help combat this, it could equally result in overeating instead.

It also bears mentioning that a diet high in animal proteins could lead to consuming too much saturated fat. This kind of fat isn’t great for your health and is a major factor in several conditions like heart disease and stroke [10].

What are the benefits of the slow-carb diet?

Beyond its potential weight loss benefits, there are absolutely a few upsides to aspects of the slow-carb diet that are backed by evidence.

  • Better control of blood sugar. The diet prioritises foods with a low GI. This means they’ll cause a lower and slower rise in blood sugar, helping to keep your glucose levels fairly stable. This can be beneficial for losing weight and maintaining weight loss, but it can also be helpful for those with insulin resistance or diabetes.
  • Stable energy levels. The additional advantage of low-GI foods is that they don’t contribute to rapid blood sugar spikes and crashes. Instead, they provide sustained energy release across the day, helping to keep your energy levels relatively stable.
  • Lower risk of some diseases. Eating low-GI foods can also reduce the risk of numerous conditions, such as type 2 diabetes, heart disease, and obesity [11].
  • High-protein benefits. Eating ample protein offers other possible health benefits, like improved bone health, lower blood pressure, healthy hormone production, and better immunity.

Are there any risks?

There certainly could be. Some of the drawbacks of the diet to consider are:

  • Lack of nutritional variety. Only eating foods from a small range of food groups could lead to deficiencies in certain nutrients — particularly those found in whole grains, fruits, dairy, and other foods that aren’t permitted on the diet.
  • Cheat day setbacks. The cheat day acts as a bit of a reset by allowing dieters to eat whatever they want, in whatever quantities. However, for those who struggle with overeating or binge eating, a day with no constraints could prove challenging and may hinder their progress.
  • Potential for disordered eating. Severely restricting the foods you can eat could lead to an unhealthy relationship with certain foods or disordered eating patterns.
  • It doesn’t work for everyone. Those with certain health issues or nutritional needs may not have their requirements met by the diet. This is why it’s always worth consulting a healthcare professional before kicking off a new eating plan — especially if you have an existing condition.

The importance of eating a balanced diet

For some people, the slow-carb diet could indeed be a sound way to lose weight and reap other benefits of a low-carb, high-protein diet.

But at Juniper, we fully believe in a diet that’s balanced, packed with a huge range of nutritious foods and drinks, doesn’t restrict certain food groups and is doable for the long term.

That’s why our Weight Reset Programme helps you implement a bespoke eating strategy that’s simple and sustainable.

It also offers guidance from a team of experts including dietitians, nutritionists and health coaches, an exercise routine to help you build muscle and lose weight, and breakthrough GLP-1 weight loss medication.

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