"Most people say you have to lose weight to be healthy, but I'll tell you the opposite. You have to be healthy to lose weight," Weaver told the Herald on Sunday.
Weaver is one of New Zealand's foremost wellness experts.
Her list of best-selling books include Accidentally Overweight, Real Food Chef, Beauty from the Inside Out and Real Food Kitchen.
She also has a raft of celebrity followers, including businessman Sir Richard Branson, actor Hugh Jackman and model Miranda Kerr.
Weaver said it wasn't just diet and exercise which are crucial to well-being in 2016 - just as importantly was how we handled ever-increasing stresses.
They can cover financial, relationship or health stresses.
In all of these situations the stress hormone cortisol is activated and it slows down the metabolism while retaining fat, she said.
Weaver often hears of stressed-out people gaining weight then going on a strict diet.
But this only reinforces your body's belief that there is a scarcity of food and makes it more difficult to lose weight. She said the key to losing weight is de-stressing and taking care of yourself.
"When you focus on weight it's all about deprivation, what you can't have. Noone can sustain that. Health is all about what you can have."
Weaver said your "beauty bits" also leave strong clues to be aware of.
White spots on your fingernails show zinc deficiency, soft nails are a sign of a lack in minerals like calcium and magnesium and nails that bend up at the ends in a spoon shape show an iron deficiency. Ridges from the top to the bottom of the nail are signs of a thyroid problem or iron deficiency while ridges from side to side show the effects of long-term stress.
Weaver said focusing on the liver is a "game changer". She recommends taking the stress off the organ by reducing your consumption of toxins like caffeine, sugar, alcohol, trans-fats and synthetic substances, while eating lots of nutrients that benefit the liver like green, leafy vegetables.
"If I had to pick on one organ for people to look after, it would be the liver it's so tied to energy."
Dr Libby Weaver's five wellness tips
• Breath deep
The nervous system communicates to our body through how we breath. Avoid short, sharp, shallow breathing. Instead breath deeply as it lowers stress hormones rapidly and benefits your biochemistry. Stress hormones cause people to gain weight.
• Eat well
There is nothing in the entire world that replaces a highly-nourishing diet. Whole and real food will ramp up the nutrition and take the stress off your liver.
• Supplement nutrition
Due to nutrient-deficient soil we can no longer rely on just foods to get every mineral and vitamin we need. Use food-based supplements, not synthetic ones as your body doesn't process them as well.
• Be happy with what you have
Stop and enjoy the good things already present in your life. When you're more connected to joy you are more likely to make better food choices and take care of yourself.
• Reduce inflammation
When you're living on adrenaline your body produces lots of inflammation. Your liver produces substances that dampen down inflammation. Care for your liver with a nutrient-rich diet and managing the stress in your lifestyle.
