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Weight Loss Programmes

Diet Doctor vs Second Nature

Megan Widdows
Written by

Megan Widdows

Medically reviewed by

Fiona Moncrieff

6 min read
Last updated July 2024

Everyone is different, and there is not a one-size-fits-all approach to choosing a weight management program. It ultimately depends on what suits your individual needs and what fits into your lifestyle. Many people find online weight management programs more convenient and easier to fit into daily life.

This guide compares Second Nature and Diet Doctor, two digital programs that provide you with evidence based educational content and advice from dieticians. With Second Nature and Diet Doctor, you’ll be able to enjoy real food and benefit from taking a lower-carb approach which, research suggests, is the best way to lose weight.

Diet Doctor is a digital program that recommends a ketogenic (keto) approach to food. A ketogenic diet is high fat and eliminates carbs almost entirely (less than 20g per day), even cutting out many fruits and vegetables.

While this may initially lead to rapid weight loss, the keto diet can be challenging to follow effectively in the long term. It’s much more restrictive and one ‘slip up’ will take you out of ketosis temporarily.

Second Nature is an easy-to-follow digital program that recommends a lower-carb approach, roughly limiting carbohydrate intake to 45-60g per day, plus fruit and vegetables. This means you can reap the benefits of a lower-carb diet, including increased weight loss and better blood sugar management, without the restriction of a keto diet.

Diet Doctor offers a free basic program with limited features, however this comparison focuses on their paid plan.

Did you know?
In the UK, Second Nature was the first ever digital behavioural change program to be commissioned by their National Health Service (NHS) and continues to be part of their weight management and type 2 diabetes management service.

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Ratings and reviews

Diet Doctor and Second Nature both deliver their program via an app enabling you to have nutrition advice in your pocket, helping you to stay on track. To compare customer satisfaction, we’ve looked at reviews from TrustPilot.

Diet Doctor Second Nature
Star rating Trustpilot reviews for Diet Doctor - 4.8/5 stars Trustpilot reviews of Second Nature - 4.8/5 stars
Score 4.8 / 5
read reviews
4.8 / 5
read reviews

Signing up

Diet Doctor Second Nature
Money back guarantee
(Full refund if cancelled within the first month. After this point, any charges non-refundable)

(Full refund if cancelled within 14 days. After this point, any charges non-refundable)
Clear breakdown of costs
Clear cancellation policy
(Cancels at the end of the subscription period)
Easy to cancel
Length of program 4 week minimum subscription 12 week minimum, then ongoing
Refer-a-friend scheme
Easy to include family


Diet Doctor Second Nature
Dietary approach Very low carb (ketogenic) Lower carb
Caters to vegetarians
Caters to vegans
(Not enough recipes to accomodate a varied vegan diet)
Vegetarian/vegan recipe section


Diet Doctor Second Nature
Tailors the plan around diabetes
(Diet Doctor recommend consulting your doctor or health care provider for specific advice)
Tailors the plan around other health issues
(Diet Doctor recommend consulting your doctor or health care provider for specific advice)
Access to a qualified nutrition specialist *
Weekend support available
Phone support available

*Second Nature coaches are all UK registered dietitians or nutritionists. This means they have completed university accredited degrees to gain this professional title. However, coaches are not registered in the US, so don’t meet the regulatory requirements to be considered US registered dietitians or nutritionists.

Program features

Diet Doctor Second Nature
Recipe videos
Exercise videos
Weighing scales provided
(on tech plan)
Encourages daily weigh-ins
Tracks sleep
Tracks steps
Tracks exercise
Tracks water intake
Education of nutrition science
Requires calorie counting
Food diary feature
Meal planning tool
In-app journalling tool


When programs provide price plans in different formats, it can be hard to accurately compare prices. To make this easier, we’ve calculated the monthly basic price plans of each program to show you how costs compare (as of February 2021).

At first glance, the Second Nature program may seem more expensive than Diet Doctor. However, the cost of the Second Nature program includes access to your coach with expertise in nutrition and wellness, alongside your digital peer support group, meal planning and journaling tools plus steps, weight, and habit tracking technology. Whereas on the Diet Doctor program, support general advice, information and, support is provided via Community Group with no access to qualified professionals.

Another option to get support with your diet would be to see a registered dietitian. Weekly face-to-face sessions with a registered dietitian can be very expensive (US$70-$100 per session). We have added a column representing this to compare costs, labelled weekly registered dietitian (WRD).

Monthly digital subscriptions:

Diet Doctor Second Nature WRD
Access to qualified nutrition specialist
The same, personal coach throughout the program
Price $9.99 / month $60 / month $350 / month

Example nutrition query response

Q: Are eggs bad for your cholesterol? Should I avoid them?

Diet Doctor answer:

Diet Doctor summarise their findings on eggs in a blog post. We’ve copied the summary, but you can read the full post here.

“Eggs are one of nature’s most perfect foods. They’re nutritious, delicious, filling, affordable, and can be prepared in dozens of different ways.

Yes, they’re high in cholesterol. But eating eggs doesn’t increase the risk of heart disease. On the contrary, when included in a healthy diet, eggs may be beneficial for heart disease risk factors. And there’s no need to toss the yolk and just eat the whites! Eat whole eggs to get their maximum health benefits, flavor, and satisfaction.”

Second Nature’s answer:

“Eggs are a rich source of dietary cholesterol. It was previously thought that cholesterol-containing foods increase blood cholesterol and the risk of heart disease and strokes. However, this has not been shown to be the case as dietary cholesterol is poorly absorbed from the digestive system, and if cholesterol is absorbed, the body will produce less of it to balance out (and prevent blood cholesterol levels rising). Therefore, you do not need to be restricted unless recommended to do so from your GP/Healthcare professional. Eggs are among the most nutritious foods on the planet providing good quality protein as well as being loaded with vitamins and minerals.”

Take home message

  • When choosing a weight management program, it is important to consider what support you need and what would fit into your lifestyle to help you achieve your goals
  • For those who find face-to-face meetings uncomfortable or inconvenient, online programs are a better option and focus on reducing carbohydrate intake
  • Diet Doctor and Second Nature are fully digital and focus on reducing carbohydrate intake
  • On the Second Nature program you will be accompanied by a peer support group – they’ll help keep you accountable every day!
  • Second Nature also includes daily access to a coach with expertise in nutrition and wellness who can answer any nutrition queries and help to tailor the program to your needs
  • Second Nature and Diet Doctor both provide you with an education of nutrition science, allowing you to make informed decisions yourself and develop a healthy relationship with food in the long-term
  • Second Nature offers phone support options, whereas Diet Doctor’s customer service is all online
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