Rachael said some of the factors that can impact your metabolism include your genes, hormones, lack of sleep, diet, dehydration, age, stress and the medications you're taking.

A personal trainer has shared the 13 signs you have a slow metabolism, and how you can boost yours to achieve your goal weight fast (Rachael Attard pictured)

Rachael (pictured) said some of the factors that can impact your metabolism include your genes, hormones, lack of sleep, diet, dehydration, age, stress and medications you're taking

But you can address your metabolism - and the PT uses a few simple 'tried and tested tricks' to give hers a boost, particularly after the holiday season, when you might be feeling sluggish from over-eating and drinking.

For this reason, she recommends a protein-rich breakfast like healthy protein smoothies, yoghurt or eggs, taking care to limit sweeteners.

But it's the resting or basal metabolic rate (RMR or BMR) that makes up 60 to 85 per cent of your daily calories burned, and the only way to increase that is to boost your muscle mass.