This month, we ask Matt about winter metabolism, food allergies and eating raw.
Q: I've heard that your metabolism increases in winter. So, does this mean I can eat more?
A: It's a nice idea, isn't it. You get to eat more just because the temperature drops.
Yes, your metabolic rate can increase in winter if the colder ambient temperature drops causing your body to produce more heat to stay warm. The result can be a boost in calorie burning from just a few percent, up to 10 percent if you shiver.
Shivering is the body's natural method of producing heat through rapid small movements. Whilst I don't recommend catching a chill in winter and stripping off too much, it can be useful to avoid being overly warm during winter.
Researchers now think that the temperature-controlled environments we all tend to live, work and play in may be contributing to obesity by not making our body's work hard to regulate our body temperature. With no opportunity to shiver, we don't get the small boost in metabolic rate.
So, shiver a little and it may allow you to eat an additional Exchange this winter. But don't use winter metabolic rate as an excuse to overeat.
Q: I am constantly hearing about food allergies and intolerances, but am confused as to what the difference between them is. Can you please explain?
A: The terms ‘food allergy’ and ‘food intolerance’ are common phrases nowadays and although they may sound similar, they are distinctly different conditions.
Food allergies are immune responses that occur when people eat specific food proteins such as peanut proteins.
Symptoms are immediate and usually obvious. They can include itchiness, hives, itchy eyes, diarrhea and vomiting, swelling around the mouth and in some cases, anaphylaxis.
The prevalence of food allergy is most common in infants and children. According to the Food Intolerance Network, up to 8% of babies, 3% of children under five years and nearly 1% of adults have food allergies.
The most common food allergies are to egg, milk, peanuts, tree nuts and seafoods. Most children grow out of their egg and milk allergies, but allergies to nuts and seafoods often persist into adult life.
Food intolerances are reactions to chemicals and/or additives in various foods.
These chemicals irritate the nerve endings in different parts of the body and cause symptoms such as stomach and bowel irritation, hives, headaches, flu-like aches and pains, and even feelings of being unusually tired, run-down or moody.
In children, food intolerance normally appears through symptoms of irritability and restlessness. It has also been associated with behavioural problems such as ADHD.
Babies normally develop colicky irritable behaviour, reflux, loose stools, eczema and nappy rashes. Sensitive babies with a susceptibility to food intolerance can have reactions even when exclusively breastfed due to food chemicals from the mother’s diet getting into the breast milk.
The speed of onset and the severity of these reactions differ from person to person. Symptoms can begin within an hour or two of intake, or take several hours to develop. Some reactions last a few hours, others can go on for several days.
Food intolerance is much more common than food allergy, with surveys indicating that up to 25% of the Australian population believing they have some sort of food intolerance.
Common food intolerances include lactose, milk, gluten and wheat. Some people are also intolerant to natural food chemicals such as salicylates (found in foods from plants), amines (a chemical that comes from protein breakdown) and glutamate (found naturally in most foods).
Q: Should I be going on the raw food diet to get the nutritional benefits of live enzymes?
A: The raw food diet involves aiming to have most of your food (75%) raw. The theory is that when foods are cooked above 48 degrees celcius, the heat ‘destroys the activity of key enzymes’, which are apparently vital to our nutritional status.
There’s a basic flaw in the science – enzymes are also denatured by acid, and when we eat foods, the strong hydrochloric acid in our stomachs inactivates enzymes in foods anyway.
Raw foodists claim that this is how our ancestors ate, but evidence from archaeology shows humans have been cooking food for around 700,000 years (0.7 million years).
A raw food diet consists of fruits, vegetables, nuts, seeds and fresh juices. Sounds healthy – yes, it is high in dietary fibre, and packed with fresh food - but it’s obviously an unbalanced approach to eating.
The next major flaw in the science is that proponents of the diet claim that cooking fruits and vegetables make them harder for our bodies to digest, and hence are in some way not as good for us.
But this is clearly wrong. When you apply heat to foods, a number of transformations take place within the food which all work to make the food more digestible; physical barriers in the food are broken down, the cells burst open, indigestible molecules are broken down into small digestible molecules and finally, toxins and harmful chemicals are inactivated.
Take lycopene, for an example. This is an antioxidant abundant in tomatoes, and studies show that the levels of lycopene are actually higher in cooked tomatoes compared to raw tomatoes.
The other thing is you’re missing on the nutritional benefits of who food groups of cooked/heat processed foods, such as dairy (protein, calcium and fat-burning) and red meat (iron, zinc, vitamin B12, omega-3 and high quality amino acids).
Studies done on the nutritional status of people who follow raw food diets show that they have reduced bone mass (linked to low dietary calcium intakes), reduced levels of vitamins such as B12, vitamin A and vitamin D.
Sticking with a nutrient-rich diet such as Metabolic Jumpstart will give you all the metabolic benefits that fruits, vegetables, dairy, cooked proteins, healthy oils and starch provide.
Want to know more about Matt and jumpstarting your metabolism? Click here.