The diet industry is making you sick, fat, and poor – that’s the claim of author David Gillespie in his new book, Big Fat Lies.

The premise is simple: almost everything we’re told about how to lose weight and be healthy is wrong. Diets don’t work. In fact, studies have shown that the best indication that an individual will be heavier in two years is if the individual is on a diet now. Vitamins, Gillespie says, aren’t actually helping you either. All they’re doing is draining your bank account and giving you very expensive urine.

What it all comes down to is sugar. It’s highly addictive, it’s in just about everything, and its prevalence has made it the root cause of most modern chronic diseases (obesity, Type II diabetes, high blood pressure, kidney disease, etc.). The polyunsaturated fats we consume (like margarine and canola oil) make us increasingly prone to the ill effects of sugar by amplifying our risk of heart disease and cancer.

So what can you do to live a life that’s actually healthy? Gillespie’s answer is simple: do not eat sugar or polyunsaturated oils and the rest will fall into place. At the supermarket, steer clear of processed foods and foods high in fructose. Don’t buy foods like margarine, jam, honey, Nutella, dried fruit, seeds (except flax seeds), low-fat milk, fruit juices, flavored yogurt, commercial desserts (like ice cream, cookies, and cakes), and dessert wines. Try to stay on the perimeter of the store, where the healthiest foods - fruit, vegetables, meat, milk, eggs, and bread – are kept.

Eat meat (ideally grass-fed and with the fat still attached), eggs, and dairy products (but beware of yogurts with added sugar and seed-oil margarine). Indulge in all kinds of fruits and vegetables, as long as they are whole rather than juiced or dried, and any nuts and seeds that are whole and fresh. Cook in animal fats, coconut oil, or olive oil. Don’t be afraid to put butter on bread (and, for that matter, don’t be afraid of bread).

At breakfast time, avoid most packaged breakfast cereals (and that goes for muesli, too), flavored oats, and liquid meals. Over lunch, don’t eat anything fried at a national franchise, jam sandwiches, or foods that are slathered in high-sugar sauces. Dinnertime should not include anything cooked with seed oil and anything cooked with a simmer sauce or commercial Italian sauce.

Follow Gillespie’s rules and you will be thinner, healthier, happier, and live a life that is big fat lie-free.