I'm a 41-year-old fitness model and I tried the restrictive carnivore diet for a month - the results were astonishing

A fitness model has revealed how her life drastically changed after adopting the 'carnivore' diet for an entire month.  

Petrina Barber, 41, who splits her time between London and Dubai, decided to cut out all processed foods and carbohydrates to help with her stoma output. 

The mother-of-one became an awareness campaigner and founded her business Beyond The Stoma after treatment for cervical cancer nine years ago led to her needing a stoma bag. 

With her new diet, that involved eating only meat, fish, eggs and a little cheese, Petrina said she wasn't aiming to lose weight but instead was looking to improve her athletic performance energy levels by solely eating animal products. 

Before going on the diet, rice, sourdough, jam doughnuts, and chocolate were favourites in her life - and the initial days saw her struggle without having her go-to snacks. 

Petrina pictured before she started the carnivore diet (left) and after four weeks eating only meat, eggs and a little cheese (right). At the end of the month, Petrina's friends and family were full of compliment,  with her husband telling her she looked healthier 

Petrina pictured after four weeks on the carnivore diet. Two people noticed that her skin was much brighter and commented on her glowing complexion 

But after just one week, Petrina said she lost weight, her craving for snacks disappeared, her sleep improved and people said she looked healthier. 

Writing for FEMAIL, she delves into the struggles and positives of the diet week-by-week... 

First week

In the first week of starting the diet, I found myself faced with immediate challenges.

On the very first day, we were engaged in an all-day activity with my son, surrounded by the temptation of burgers and fries. I hadn't adequately prepared for this diet transition, and my usual diet leaned heavily on good carbs. 

As a result, I quickly realised the need to increase my intake of quality-sourced protein and consequently, calories. Those initial days were tough, I was underprepared, lacked meal planning, and struggled to come up with food ideas. On top of that, I had an awful headache and just a general feeling of tiredness.

I soon realised that I was a snacker. I usually had a slice of toast or a jam doughnut almost every day, and without those now on the menu, I had to think through my options. Snacking on meat didn't seem appealing at first, and what I learned was that it was important to fill yourself up at each individual meal.

Petrina opted for beef carpaccio (left) when dining out while a typical lunch was made up of steak and eggs (right)

As a snack Petrina would opt for bone broth (pictured), a favourite of wellness influencers like Gwyneth Paltrow

After the first few days, my cravings vanished, along with the dips in energy that would often follow my previous snacking habits. It dawned on me that I no longer desired snacks while following the carnivore diet, I found myself constantly full and content.

Within the initial four days, I lost 2kg, and though I ultimately lost a total of 4kg, my weight eventually stabilised. 

Since I hadn't aimed to lose weight, I shifted my focus to maintaining it. This was a natural progression for me, and I had no desire to continue losing weight beyond what my body naturally adjusted to.

I felt terrible during week one. I was exhausted - I thought it might be the case for a few days, but not as long as it went on. I still had a pounding headache and a foggy memory. 

But I was fully aware it takes one to two weeks to transition your body to the new diet as it needs to reconfigure how you get glucose from switching fuel supplies.

I was still training at the gym, and my workouts were at the same level as they were previously, so I saw no difference in training performance even though I felt tired.

On day five, I received vitamin D and B12 shots and underwent blood work. I opt for injections as my body, due to health issues and pelvic radiation disease, struggles to absorb supplements orally.

Some people do not deal well with fibre, especially after bowel resection, so I gave up fruits and vegetables around two years ago. 

It's common with certain medical conditions they exacerbate symptoms and so the definition of a 'healthy' diet is always relative ultimately. 

Despite a common belief suggesting potential nutritional deficiencies, regular blood tests have shown no issues as long as I maintain my B12 and VitD shots. I believe it's perfectly plausible to eliminate them from a diet and still be healthy. Everyone is just different.

The first weekend on the diet was so hard. I wanted to eat the usual foods I associate with family time on weekends, especially doughnuts. 

I also could have eaten better choices at lunch because they were too low in fat. Chicken and egg whites didn't make me as full, so while it was enjoyable, I struggled with not feeling full afterward. 

Then I had to make avocado toast for my son, and I wanted to eat some. I love the taste of avocado and carbs. When we got home I felt tired and lacking any energy and I struggled not to have a jam doughnut. It was more out of habit and fatigue rather than a genuine desire. 

Later, we went out for dinner, and it was incredible. I indulged in beef carpaccio and steak, leaving me feeling very satisfied and full.

Petrina would sometimes have beef mince with cheese and three eggs (left) for lunch but once had to resort to McDonald's burgers (right) when she was out of the house for longer than expected 

Second week

In week two, I found it easier to fall asleep and remain asleep. Already, I noticed changes in how my clothes fit. I appeared leaner with more muscle definition.

I read lots of advice suggesting daily exercise during the diet. However, I did the opposite and pulled back on my workouts to conserve energy but increased the intensity of the workouts and have more active rest and recovery time instead. 

This helped me stick to the routine and make it through the early days of the diet feeling less fatigued because I knew I wasn't running myself into the ground. My workouts were powerful, consisting of weight training three times a week and one cardio session.

I went out for lunch with a group to socialise and it was easy to select food without standing out like I needed to eat certain foods. 

I simply modified some starters and had a large steak for lunch. I didn't look or feel like a social pariah. That was a huge benefit. I had more comments with lunch on how well I looked.

I had no cravings after lunch for dessert or anything sweet, which usually happens to me. But, while my husband was stuffed after lunch,  I needed to eat more. So, I had some quick-to-cook burgers.

While it wasn't her intention to lose weight, Petrina noticed an overall weight loss of 4kg, as well as a brighter complexion 

Petrina continued to exercise, doing three weight training sessions (left) a week plus one cardio session. By the second week, she'd noticed that her clothes fitted differently - she looked leaner with greater muscle definition 

Third week

Knowing what I'm going to eat, planning in advance and buying the food ahead of time helped me stick to the diet more easily this week.

But I was shocked at how easy it is actually to under eat. I started the diet by tracking what I ate, and I am glad that I did because it showed me I was way off the mark.

I wasn't picking the right foods initially. I'm on the diet for stoma output and because I believe it will have implications for my overall health - not to lose weight. 

That said, anyone switching to a carnivore diet would experience significant decreases in weight, as it's very, very hard to overeat on this diet when you cut out all processed food and carbs. My concern was that I would drop too much weight, but the fact that I have found equilibrium is encouraging. 

I love the food. It felt relatively easy for me to eat protein all day, every day, as it's my favourite type of food.

Fourth week

For my final week, the people around me were full of compliments. Two people noticed my skin was much brighter and commented on my face. My husband said I look healthier.

At the end of the month, I am active overall and doing three high-performance strength training sessions a week. I dropped cardio. I have a lot of energy, and that's no longer an issue but I do not want to lose more weight.

If you're going to stick to the carnivore diet, you need to get into the habit of making your own food from scratch, said the fitness model. Petrina made her own burgers (left) which she ate with cheese (right) for lunch

Since meal prep was such a big part of the carnivore diet, Petrina doubts that you'd be able to make it through a day, let alone a week, if you're not willing to spend time in the kitchen

I don't get those periods of hunger or need to snack anymore. I used to eat breakfast, and I would want something afterwards, like another slice of toast. Or I would have dinner and want something sweet afterward. 

I've found that I don't have cravings, which is shocking because rice, sourdough, jam doughnuts, and some chocolate were daily staples in my diet. I thought I would be folding under the pressure of wanting a jam doughnut by now, but I'm doing OK.

I have realised how organised you need to be on this diet. I am usually very organised when it comes to food, but if you don't plan and prepare, you are unlikely to make it through one day, let alone a week. It's not a diet where food is easily accessible in an emergency. You can't just pick a sandwich up and eat the filling.

Like with any diet, you'll probably already have some entrenched habits that will be hard to break. For me, there was a lot around the weekends, and I associate eating with my family, so that was very difficult. 

The carnivore diet is no joke, especially with the difficulty of the first few weeks and the side effects. I can understand why many people abandon the diet or find it too challenging.

But for me, overall, I felt it was a huge success, and I am sticking to the diet for the foreseeable future.