Cambridge Diet: Is the popular plan right for you?

One of the most popular diets in the UK, what is the Cambridge Diet really all about?

a collage showing the Cambridge diet meal plan

The Cambridge diet provides portioned meals and one on one professional support to those following the tailored weight loss programme. 

Whilst it may not be a quick-fix extreme diet, the Cambridge Diet is certainly one of those diets that works fast to achieve results thanks to it's low fat, carb and calorie focus. A specially designed 5-step eating plan, dieters start the plan on select Cambridge Diet designed low-calorie meals in place of their regular breakfast, lunch and dinner. Before slowly re-introducing and returning to their normal diet after dropping the pounds.

"The Cambridge diet certainly has its pros, providing calorie controlled meals to people wanting to lose weight whilst being on the go," says Nutritionist Emma Thornton. "However it personally wouldn’t be my first choice in most cases due to it centring around more processed food options. I prefer to recommend people prioritise fresh, wholefoods and take a more holistic lifestyle approach to health in general."

What is the Cambridge diet?

The Cambridge diet is a balanced low-fat, low-calorie, lower carb diet.

Much like the Jane Plan diet, it's a specific targeted programme that dieters pay a fee to sign up to. In exchange, you receive meals, resources and a tailored plan to help you lose weight.

"The Cambridge diet is a consultant-lead diet plan largely centred around meal replacement foods, which is somewhat tailored to the individual," explains Emma Thornton, a qualified Nutritionist at herbal remedies company A.Vogel.

It was originally devised by Dr Alan Howard at Cambridge University in 1970 (hence it's name). He came up with a calorie-restricted regime to help obese patients shed the pounds. And the method returned promising results, leading to it's inception as a worldwide programme. Today's model sees dieters eat meal-replacement meals, bars, soups and shakes. Which are both low- calorie and contain the recommended daily allowance of vitamins and minerals.

It's been re-branded as the 1:1 diet in recent years because part of the package includes a consultant who you check in with weekly whilst following the diet. During this meeting you'll buy your food packs – you can only buy these from a registered and trained counsellor. Plus be able discuss your progress with the Cambridge Diet and talk about your issues and difficulties, if you have them.

An average week on the plan will set you back £55.23. Which includes your three daily Cambridge diet replacement meals and weekly consultation.

How does the Cambridge diet work?

The Cambridge diet works by making the body burn fat - and in turn lose weight.

The principle of the plan is that with the right amount of protein, carbohydrate, fat, very few calories and the recommended daily allowance of vitamins and minerals - your body gets all the nutrients it needs. Whilst subsequently using its fat stores for energy, therefore burning fat.

Limiting carbohydrates, as the Cambridge diet does, has a knock on effect on our glucose levels. Which is usually the body's main source of energy.

"Due to the significantly reduced intake of carbohydrates, your body starts producing high levels of “ketone bodies” from fat,” explains Flo Seabright, nutritionist, PT and founder of FBF Collective. "These are prioritised to help fuel the body, rather than using glucose.”

Known as ketosis - a similar state that occurs when following the keto diet - your body burns fat cells leading to weight loss. And indeed science supports this, with a 2018 study highlighting that ketosis leads to excess fat loss and improved control over sugar levels.

What's more, as the Cambridge plan is a high protein diet, you don’t lose muscle mass or have cravings, like on other plans.

A 2018 Oxford University study followed a group of participants on the Cambridge diet and the results spoke for themselves. After a year, those who followed the plan (alongside one to one support) had reported an average weight loss of 10.7kg. That's over 1 and a half stone.

What can you eat on the Cambridge diet?

What you can eat on the Cambridge diet is dependent on what step in the plan you are on.

For example, in the first phase you'll be asked to eat 3 Cambridge Diet food packs a day, with little else allowed. The number of replacement meals then decreases and returns to regular but healthy breakfast, lunch and dinner options as you progress.

The idea is that each meal replacement product is around 200 calories. So you start on very little calories and gradually introduce more calories slowly. H20 is also important on the plan, with it recommended that you drink plenty of water (about 8 large glasses) a day.

The six different steps are as follows:

  • First step: You'll start the diet prescribed with the Sole Source or Sole Source + step. This phase will last between 1-12 weeks. And is assigned to you by a 1:1 diet nutritionist who has based this step on your individual needs. On Sole Source you will eat 3-4 Cambridge Diet meal products a day (totalling 415-554 cals) Whilst Sole Source + entails 3 Cambridge Diet meals + 200ml of skimmed milk a day (totalling 615 cals).
  • Second step: The next phase includes 2 Cambridge Diet meals plus protein-rich foods, 1/5 pint of skimmed milk and some vegetables (totalling 810 cals)
  • Third step: For two weeks you can enjoy 2 Cambridge Diet meals and skimmed milk. In addition to a healthy low-calorie breakfast and salads for lunch and dinner (totalling 1000 cals).
  • Fourth step: The next fortnight feature 2 Cambridge Diet meals and skimmed milk. Plus a normal breakfast, lunch and dinner. (Totalling 1300 cals)
  • Fifth step: The last phase takes you down to just 1 2 Cambridge Diet a day for two weeks. Continue to drink skimmed milk and eat a healthy breakfast, lunch, dinner and snack. (totalling 1500 cals)
  • Maintenance: To be continued indefinitely, enjoy a regular healthy diet. And add in your choice of Cambridge Diet products to keep you in line now and again.

Example Cambridge diet meal plan

For step 5 you have one food pack, three regular meals and one 100 calorie snack:

Breakfast: A fruit smoothie - like this Blueberry and kiwi smoothie. Plus 3 rye crispbread with low-fat cream or cottage cheese

Lunch: Roast tomato and orange soup with a small granary roll filled with cottage cheese. A 100g pot of low-fat fromage frais for pudding.

A photo posted by on

Dinner: Try a Prawn and cucumber stir-fry or a Chicken and prawn paella with one vegetable portion or a small piece of fruit.

Snack: Two chocolate chip cookies or a bowl of fruit with a dollop of good for you greek yogurt.

Which foods should you avoid on the Cambridge diet?

One of the biggest things you have to avoid when on the Cambridge diet is alcohol.

Dieters are asked to stop drinking alcohol throughout all five of the steps. In fact, during the first few steps you're only allowed to drink water, herbal tea or regular tea and coffee without milk.

Milk is also not allowed or restricted to just 200ml a day in the first phase. (depending on what plan you're on). And it specifies that the milk must be skimmed. So kiss goodbye to your full-fat and semi-skimmed days.

Is the Cambridge diet safe?

Yes, the Cambridge diet is safe.

According to their website, the 1:1 plan was developed, tried-and-tested by employed nutritionists and health professionals.

Independent nutritionist Emma Thornton agrees: "The foods contained in the Cambridge diet are safe in that they provide sensible calories and are well balanced in terms of the nutrients they contain. Therefore, it’s likely they are ‘safe’. Although whether or not they are optimal for health, would be a different consideration."

The Cambridge diet programme prides itself on being deemed safe and actually beneficial for those with diabetes too.

A recent DiRECT study incorporated some of the plan's products and strategy in a weight management programme with overweight individuals who have type 2 diabetes. Following a restricted 850-calories-a-day diet, they found that 45.6% of participants were in remission from the condition after a year.

As with any diet, it is important to consult with your doctor before trying something new. Especially if you have concerns.

Pros and cons of the Cambridge diet?

✅  Weight loss - The Cambridge Diet website and social media pages are full of success stories. And of course there's the Oxford University study - which found that after a year participants on the plan lost over 1 and a half stone.

✅  Nutrients - The Cambridge diet promises that each meal replacement contains the required vitamins and nutrients your body needs to function properly.

✅  Support - "The 1:1 support that comes with the 1:1 diet is a nice benefit," says Nutritionist Emma. "Sometimes people need a little moral support or motivation if they are keen to really make lasting changes to their diet or lifestyle."

✅  Straight-forward plan - The Cambridge diet sets out what you can and can't eat during each stage. People that like a diet with a clear structure may find this helpful.

❌  Expensive - A weekly plan with 3 Cambridge Diet meals costs over £50. That adds up to over £200 a month which some people might not be able to afford or justify paying.

❌  Side effects - Common side-effects of ketosis are bad breath, headaches and lethargy for the first three days. And participants in the Oxford University study reported these plus constipation and dizziness too. It's important to note that not everyone experiences this. But these can be troubling side effects.

❌  Lack of fresh foods - Of which Nutritionist Emma says the 1:1 diet is severely lacking. "Whilst the foods including in the plan include essential nutrients, these aren’t found in the natural form which the body is able to recognise and utilise optimally. Other healthy dietary components such as dietary fibre may also be lacking due to the lack of fresh foods, and the inclusion of additives such as artificial sweeteners will be high. These can create issues for areas of our health such as the balance within our gut microbiome."

❌  Drinks - Some people find it hard to drink 8 large glasses of water a day. And you are not allowed to have chewing gum, diet drinks or tea and coffee with milk on the 1st and 2nd step of the programme.

❌  Restricted calories - Like any diet, you need willpower. And it can be hard to stick to in the beginning. Especially when some days you're only allowed around 500 calories. Some people may also find themselves not a fan of some of the meal replacement options.

The Cambridge diet - a nutritionists verdict

Nutritionist Emma Thornton is unlikely to recommend the Cambridge diet to her clients. This is due to it's processed foods nature and the fact that it's not considered a sustainable long-term weight loss method.

"The 1:1 diet may be helpful for some people who require some guidance - for example, helping to gain some understanding around calories," says Emma. "But I’d personally opt for a more fresh food approach."

"Fresh foods are the most appropriate source of nutrients including vitamins, minerals and fibre. Which our body can make the best use of. Combining fresh foods alongside other important key diet and lifestyle habits such as drinking enough water or eating mindfully and minimising stress can usually help to facilitate a calorie deficit (if required). So I don’t believe meal replacements are necessarily needed to achieve this."

She adds that set meal plans are also not suitable for everyone for several reasons:

"They can be expensive, stressful and can risk taking the fun and imagination away from cooking, eating and enjoying real foods.

"I prefer to remind people of the more healthful foods. Making them aware of options which aren’t usually so healthful, and help people to plan their own, freshly prepared meals around key ingredients. This means people can also tailor a longer-lasting, healthy diet and lifestyle regime which is in line with their own individual finances and time constraints."

Emily Stedman
Features Editor

Emily Stedman is the former Features Editor for GoodTo covering all things TV, entertainment, royal, lifestyle, health and wellbeing. Boasting an encyclopaedic knowledge on all things TV, celebrity and royals, career highlights include working at HELLO! Magazine and as a royal researcher to Diana biographer Andrew Morton on his book Meghan: A Hollywood Princess. In her spare time, Emily can be found eating her way around London, swimming at her local Lido or curled up on the sofa binging the next best Netflix show.