Day 28 of our Bitesize Nutrition challenge is to optimise your energy through eating a balance of nutrients. Probably the most frequently asked question Nutritionists get asked is “What’s the best diet?”.

Here’s some of the popular diets:

  • Ketogenic
  • Low carbohydrate
  • Paleo
  • Vegan
  • Intermittent fasting
  • Slimming World
  • SlimFast
  • WeightWatchers

In all honesty, there’s no one diet for everyone as we’re all different. And if you do find a way of eating which works well for you, don’t be surprised it may work well for a while, but as we age it may not always continue to be the right one for you.

How you choose to eat will depend on various factors:

  • Your level and type of exercise
  • Genetics
  • Body type
  • Food availability
  • Financial
  • Dietary preference (limitations on excluding certain foods e.g. dairy, gluten)
  • Available time (e.g. work, family)
  • Season (Spring, Summer, Autumn, Winter)


Low carbohydrate (5%) high fat (75%), and protein (20%) diet encouraging the body to burn fat for energy.

✔- Fat reduction whilst eating high fat foods, less hungry

X – Takes approx. three weeks to move from burning carbohydrates to burn fats, restrictive, missing fibre and nutrients from not eating 5-a-day, constipation, sub-optimal health during three week transition over to fat burning, not advisable if have kidney disease

Low carbohydrate

Cutting down (not removing completely) carbohydrates. Suggested less than 130g per day (slice bread is 15-20g, jacket potato is 90g).

✔ – Easy to maintain over longer term, doesn’t exclude any food groups.


Hunter gatherer diet (meat, seafood, eggs, nuts, seeds, fruit, vegetables). Cereal grains (wheat), dairy, refined sugar, potatoes or anything processed or with added salt are excluded. This diet tends to be high protein and low carbohydrate.

✔ – Encourages eating less processed food which are high in sugars, and including more fruit and vegetables.

X – Encourage more meat eating which depending on type of meat may be linked to various health conditions. Excluding dairy products could lead to dietary deficiencies if not replaced with foods fortified with missing vitamins and minerals.


Plant based diet (vegetables, fruit, grains, nuts) without eating foods which come from animals including dairy and eggs.

✔ – Improve weight, health and the environment.

X – Can be restrictive when newly adopting it leading to sudden weight loss and being hungrier than usual reaching for highly processed foods, lacking in B12, folate, calcium and omega-3, can feel bloated initially when moving to more legumes

Intermittent fasting

The most popular variation of intermittent fasting is the 5:2. Eating “normally” for 5 days and fasting to around 600 or 800 calories per day two days per week.

✔ – Flexible (can choose which days are fasting days and they’re movable), good for maintenance being less severe fasting just two days per week.

X – Possible overeating on non-restrictive days, restricted days may not have sufficient nutrient balance, possible low blood glucose symptoms on fasting days (irritability, shaking, light headed).

Slimming World

Switching high fat for low fat options eaten in unlimited amounts e.g. vegetables, fruit, pasta, rice, potatoes, lean meat, fish, eggs. Healthy extras are milk, cereals, wholemeal bread, cheese with no banned food.

✔ – No banned foods, support from fellow members at weekly group meetings and an exercise plan is provided.

X – Unrestricted amounts could lead to overeating.


Low-calorie meal replacement 3 snacks a day (including crisps and chocolate), two meal replacement shakes/bars and one “normal” meal from a list of recipes.

✔ – Convenient and doesn’t require any knowledge of nutrition or portion sizes, no foods forbidden.

X – Rebound weight gain when target weight has been reached, difficult to get variety and nutrition balance, doesn’t teach about food – just drink a SF shake.


Foods and drinks are given a value (points) depending on their protein, carbohydrate, fat and fibre content. Personal SmartPoint allowance to use throughout the day. Unlimited fruit and vegetables. Earn points through exercise, and weekly meetings and weigh-ins for additional support/motivation.

✔ – No banned foods, SmartPoints possibly easier to follow than counting calories.

X – Initially takes time to understand points system, pressure to buy WeightWatchers products

Losing weight the healthy way

It’s all about small sustainable changes that you can include every day without much hassle. Drastic weight reduction often results in weight gain shortly after target weight has been reached – weighing more than when you started! Aim for 0.5-2lb loss per week.

  • Drinking one more glass of water and eating one more vegetable will help to fill you for a while reducing cravings for sweeter foods.
  • Understand how to read food labels to you can spot the hidden fats in products
  • Switch white pasta/rice for wholemeal and white bread for granary/seeded
  • Choose a smaller plate at meal times
  • Replace fizzy drinks with sparkling water
  • Reduce sugar in hot drinks
  • Cut down alcohol
  • Switch an unhealthy snack for a healthy one

Achieving a healthy weight and being in good health is about eating well, lots of variety of foods and in a variety of colours to maximise the nutrients. A good example of what your plate should look like in terms of balance between the food groups can be found here.


Exercise is hugely important. Put simply, if you restrict your food intake and you don’t use your muscles your muscles will start to be used up for energy so it’s not just fat you’re losing. When target weight has been reached and eating returns to “normal” there’s less muscle available to burn up the additional foods so fat mass is more than before and muscles are less.

If you’d like to find out more tips to improve your health, check out our webinars and our Bitesize Nutrition podcasts. If you’re new to podcasts you can listen free without registration on your phone or PC by clicking on the podcast link in this paragraph. Or you can listen to Bitesize Nutrition on iTunes & Spotify.

Don’t forget to let us know what you think using #nutritionchallenge30

A reminder:

  • The information in this article is for educational purposes and should not replace medical advice.
  • The information is not intended to diagnose or treat any medical condition.
  • If you have a diagnosed medical condition, you should consult a doctor before making any major changes to your diet, and;
  • Some supplements may interact with medications and you should check with your GP before commencing any supplement programme.
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