It’s easy to miss out on key vitamins and minerals if you’re cutting calories. The doctor behind Channel 4’s The 21 Day Body Transformation and Fast 800 Diet explains how to make sure you’re getting enough

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If you’re eating fewer calories in order to lose weight, it’s very common to miss out on vital nutrients, especially if you’re not eating a balanced diet. Quite often people will choose ‘low fat’ as their diet approach. This means that fat-soluble vitamins (those that need fat to be absorbed - vitamins A, D, E, K) are the first to slip. If you’re a vegetarian, or vegan, or cutting down on meat and dairy and you’re trying to lose weight,  iron  can be hard to maintain, as can certain B vitamins.

A surprising number of people who are overweight or obese are deficient in certain vitamins and essential minerals and they may want to take a multivitamin. In a  recent study , where researchers from Curtin University in Perth, Western Australia tested the blood of 127 overweight or obese individuals with an average age of 49, they found that most of them were deficient in vitamin A, vitamin D, vitamin E, folic acid, potassium,  zinc ,  calcium  and  magnesium .

One of the striking things we found while making my recent series for Channel 4, The 21 Day Body Transformation with Michael Mosley which started last week, is that all our contributors were short on critical vitamins and minerals at the start, which was soon corrected by giving them our  Fast 800 Multivitamin . The reason we created it was because I'm often asked if it is necessary to supplement our diets when fasting, and if so, which supplements to take. The Fast 800 Multivitamin contains all the essential nutrients which the Perth scientists tested for as well as others such as selenium, calcium, and  iodine , which were considered essential to include.

Why do you need iodine for weight loss?

Iodine  is mainly found in white fish and cow’s milk and people in the UK have some of the highest rates of iodine deficiency in the world. Iodine is vital for a healthy thyroid gland, which in turn helps control your metabolism. Iodine deficiency can lead to hypothyroidism (an underactive thyroid gland) which often leads to weight gain.

Why do you need selenium for weight loss?

Selenium is a powerful antioxidant that plays a crucial role in your metabolism. A recent Italian study found that giving selenium supplements to obese patients who were dieting helped with weight loss.

If you’re vegetarian, vegan or in the process of reducing your meat and dairy consumption, vitamin B12 and vitamin D3 are hard to come by through plant-based food alone. Women over the age of 50 have a higher risk of being deficient in vitamins B6, B12 and  vitamin D . Also, they require more calcium.

MORE GLOSS: The supplements to take if you're vegan – and why 

Why do you need calcium for weight loss?

Studies show that those who are deficient in calcium tend to be overweight and that when that deficiency is resolved, it can often lead to weight loss. Calcium helps you feel fuller for longer and helps burn fat.  Other research reports that calcium may prevent regaining weight after successfully losing it.

When’s the best time to take supplements?

I take them in the morning with breakfast. With food is best just because some people can feel nauseous taking tablets on an empty stomach. It also can improve absorption. I would avoid taking at night, purely because B vitamins can keep some people awake - it also means you have all day to best digest, absorb and utilise the nutrients.

Of course, check with your usual healthcare professional - they may have advice on which supplements are suitable for you.

What happens if you miss out on vitamins and minerals when you’re dieting or fasting

Tiredness, hair fall and snacking

Usually, if people are lacking in nutrients, they will feel lethargic or notice that their immune system is not quite functioning optimally. Some people feel like their brain is foggy. Naturally, having less energy or brain fog will make you feel more like snacking for a quick boost, which can lead to overeating quite easily, or snacking on less than healthy options. Some people experience brittle hair and nails.

Lowered immune health

In the time of Covid-19 it’s especially important not to miss out on immune health vitamins and minerals. Any of the nutrients involved in immune processes (vitamin C, E, A, and D, also iron) are all necessary. They’re really important for optimal functioning of the immune response. For example, vitamin C can be a tricky one to stay on top of – we don’t have massive stores in our body, (unlike iron for example) so we need to replenish it regularly.

Unfortunately, it’s a vitamin that gets used up quickly when we become stressed, so it’s even more important to be aware of your intake during Covid 19. While it’s readily available in fruits and vegetables, it’s important to note that as a water-soluble vitamin, C can be considerably diminished when cooked - so ensure you’re eating a mix of raw and cooked vegetables.

MORE GLOSS: Why liposomal vitamin C is the powerhouse formula we should all be taking

As well as micros, be sure to get enough protein

One macronutrient to be mindful of is protein. If lacking in protein, you may experience muscle wastage, lacking energy and hair loss.

Dr Michael Mosley's weight loss-friendly vitamin-rich foods and 'super meals'

1. For immune bolstering: vitamin C, vitamin D, selenium and zinc.

These are all essential for a healthy immune system, crucial for fighting infectious diseases. Look for...

Vitamin C: found in raw fruit and vegetables particularly red, orange, yellow and green.

Vitamin D: found in sunshine and oily fish, red meat, egg yolks and fortified foods. Mushrooms can convert sunlight to vitamin D - just put your raw mushrooms on a sunny windowsill and through this additional vitamin D2 is stimulated.

Selenium: Just two to three Brazil nuts can provide enough daily selenium. Also found in eggs, sunflower seeds, oysters.

Zinc: helps fight off invading bacteria and viruses and with wound healing, also important for senses, taste and smell. Found in oysters, animal proteins, beans, nuts, whole grains.

Your immune supermeal:  Fish and chips

It includes oily fish for vitamin D and zinc, fresh rocket and lemon juice for vitamin C. Replace the almond meal with ground Brazil nuts and you’ve got selenium! This  Fish and Chips for Fasting  recipe has it all.

2. For energy: B vitamins, C and iron

We need vitamins and minerals for energy. Look for...

B vitamins: all the B vitamins are involved in the Kreb’s cycle (citric acid cycle), which is how we create energy in the body.Lacking B vitamins, means lacking energy. Found in oily fish and seafood, organ meats (liver, kidneys, etc), eggs, dairy products, beef, legumes

Vitamin C: is required for energy-yielding metabolism and iron absorption. Found in raw fruit and vegetables particularly red, orange, yellow and green.

Iron: is required for blood oxygenation, which helps our muscles to function well. Found in red meats, poultry, dark green leafy vegetables (cooked is better) - eat with vitamin C for maximum absorption

Your energy supermeal:  Asian beef salad
This includes lots of raw vegetables and citrus for vitamin C, beef for iron and B vitamins3. For cognitive function and brain health: zinc, magnesium, copper and iron, vitamin E
These are all important for brain health, while studies have shown a higher intake of vitamin E is linked to slower cognitive decline in older people.Vitamin E: nuts and nut oils, seafood, poultry, beans, animal proteinsCopper: oysters, nuts and seeds, leafy green vegetablesIron: red meats, poultry, dark green leafy vegetables (cooked is better) - eat with vitamin C for maximum absorptionZinc: oysters, animal proteins, beans, nuts, whole grainsMagnesium: cocoa, whole grains, green leafy vegetables, nuts and seeds
Brain health supermeal: 
Prawn cocktailor  Mediterranean tuna salad

4. For skin, hair and nail health: vitamin C, E, D, selenium
Collagen is a protein responsible for healthy joints and skin elasticity. It's in your bones, muscles, and blood. As you age, your existing collagen breaks down, and it gets harder for your body to produce more so ensuring collagen production is vital to healthy hair, skin, nails and healthy aging.Vitamin C: is essential for the production of  
collagen , one of the main building blocks of bones, skin, hair and muscles,Vitamin E: protects the skin from sun damage. Found in nuts and nut oils, seafood, poultry, beans, animal proteinsVitamin D: can help prevent skin ageing. Found in sunshine and oily fish, red meat, egg yolks and fortified foods.Vitamin A and zinc: also contribute to the maintenance of healthy hair. Vitamin A is found in animal proteins, organ meats, oily fish, egg yolks, orange, yellow and green veg. Zinc is found in oysters, animal proteins, beans, nuts, whole grainsSelenium: is also vital for healthy hair, skin and nails. Found in Brazil nuts
Your skin and hair supermeal: 
Mediterranean omelette- add a side of wilted spinach for iron
This provides extra nutritional support if your vegetarian or vegan.5. For vegans and vegetarians: vitamin B12 and vitamin D3
These are hard to come by through plant-based food alone if you vegan or in the process of reducing your meat and dairy consumption. B12 and D3 don’t exist for vegans unless in fortified foods. The Fast 800 multivitamin is vegan-friendly has your daily 100 per cent NRV (nutrient reference value) of both vitamin B12 and D3, along with iron and zinc.What to eat:
For iron and zinc - choose vegetable sources from above such as dark green leafy vegetables (iron) and beans, wholegrains, nuts and seeds for zinc, especially sunflower seeds.
Your vegan supermeal:
Kimchi Tofu Rice Bowl.

The Fast 800 Multivitamin, £14.44 for 90 tablets

The Fast 800  is an approach to healthy living and weight loss based on the latest scientific research. The Fast 800 online programme has been developed in conjunction with Dr Michael Mosley for those that need more support and guidance for achieving long-lasting health.