What is the Cambridge Diet Step 1?
Step 1 of the Cambridge Diet, officially known as The 1:1 Diet, is called the 'Sole Source' phase. It is the most restrictive and intensive part of the plan, where all conventional food is eliminated in favor of branded meal replacement products. This step typically lasts for a maximum of 12 weeks and is designed to create a significant calorie deficit (around 400-600 kcal per day) to induce a state of ketosis, where the body begins burning its own fat stores for energy. Because of the severity of the calorie restriction, it is crucial to undertake this step under the guidance of a qualified 1:1 Diet Consultant. The consultant provides personalized support, helps select the right products, and monitors your progress.
The Purpose of the Sole Source Step
For many, the Sole Source phase serves as a powerful jump-start for weight loss. The structured nature of the plan removes the need to make food choices, count calories, or prepare complex meals, simplifying the dieting process immensely. This intense focus allows dieters to break unhealthy eating habits and reset their relationship with food. The products are formulated to be nutritionally complete, providing all the necessary vitamins, minerals, and protein needed for safe weight loss, despite the low-calorie count.
The Menu: What Products Are Permitted?
On Cambridge Diet Step 1, your entire daily intake of calories and nutrients comes from the range of 1:1 Diet products. The specific number of products you consume per day is determined by your consultant and typically falls between three and four. Women under 5’8” usually have three products, while taller women and all men have four.
Here is a breakdown of the types of meal replacement products you can expect to consume:
- Shakes: These are one of the most popular options and come in a variety of flavors, including chocolate, strawberry, vanilla, and cappuccino. They are quick and easy to prepare, offering a convenient meal replacement on the go.
- Soups: For those who prefer a savory option, the plan offers a selection of hearty and flavorful soups, such as leek & potato, chicken & mushroom, or oriental chilli. These can be especially comforting during colder months.
- Porridge and Cereal: To start the day with a warm meal, dieters can choose from various porridge flavors like original, apple & cinnamon, or mixed berry. Some locations may also offer low-calorie cereals.
- Bars and Bites: The 1:1 Diet provides a range of bars and small bites that offer a satisfying chew. Flavors include peanut crispy, chocolate chewy, and lemon yoghurt bars, as well as salted caramel bites. These are ideal for curbing cravings and provide a more substantial feeling than a shake or soup.
- Smoothies: A refreshing alternative to shakes, smoothies come in fruit-based flavors like apple & blackcurrant or cherry & strawberry.
Fluid Intake: The Essential Component
During Step 1, a significant amount of fluid intake is mandatory. Dieters are required to drink a minimum of 2.25 litres (or 4 pints) of fluid per day. This is vital for several reasons, including preventing dehydration, assisting the body in flushing out waste products from fat breakdown, and helping to manage hunger.
Approved fluids for Step 1 include:
- Water (still or sparkling)
- Black tea or coffee (no milk)
- Herbal and fruit teas
- The 1:1 Diet water flavorings
It is important to note that diet fizzy drinks are not permitted on the Sole Source step, and milk is completely restricted.
Comparison: Cambridge Diet Step 1 vs. Step 2
To provide context on the restrictiveness of Step 1, here is a comparison with the subsequent step of the diet plan.
| Feature | Cambridge Diet Step 1 (Sole Source) | Cambridge Diet Step 2 |
|---|---|---|
| Primary Food Source | Exclusively 1:1 Diet products | 3 x 1:1 Diet products PLUS a small, protein-rich food meal |
| Daily Calories | 400-600 kcal | ~800 kcal |
| Fluid Intake | Min 2.25 litres water/allowed drinks | Min 2.25 litres water/allowed drinks, including occasional diet sodas |
| Conventional Food | None allowed | Small portions of protein and vegetables introduced |
| Plan Duration | Maximum of 12 weeks | Typically 2 weeks |
Potential Side Effects and Considerations
The very low-calorie intake of Step 1 can lead to some side effects as the body adjusts to ketosis. These may include headaches, dizziness, fatigue, nausea, bad breath, and constipation. Proper hydration is key to minimizing these symptoms. The diet's developers acknowledge these side effects and recommend consulting a healthcare professional, especially for individuals with underlying medical conditions. The intensity of this phase also requires strong mental fortitude, as it can be socially challenging and feel monotonous for some.
Conclusion
For those asking what can I eat on Cambridge Diet Step 1, the answer is straightforward but strict: only the specialized meal replacement products provided by The 1:1 Diet. The regimen, while challenging, is designed for rapid and impactful initial weight loss. By following the plan under the guidance of a consultant and maintaining high fluid intake, dieters can effectively kick-start their journey. However, it is essential to be prepared for the diet's restrictive nature and potential side effects. Always discuss starting a very low-calorie diet with a healthcare provider to ensure it is the right and safe option for you. Transitioning to later steps involves a gradual reintroduction of conventional foods, paving the way for long-term weight management.
