If you’re eating less to lose weight, it seems to make sense to cut as many calories from your diet as possible. Unfortunately, it’s possible to eat too little, which not only makes it harder for you to achieve a healthy weight, but it can also cause other health problems. In other words, eating below your needs can backfire big time.
When it comes to losing weight or trying to find a quick fix to get lean, there is a lot of information available on the Internet. Unfortunately, large chunks of it are mere myths in the disguise of a hack or a trick. It is, therefore, extremely important to get the right advice before you begin to turn your routine into your lifestyle. For instance, one of the most common myths when it comes to shedding those extra pounds is eating less.
When it comes to losing weight, everyone seems to have a solution: cut carbs, start running, try a juice fast. While you may lose weight following any of these suggestions, keeping it off may not be that easy. Most health care professionals recommend a combination of diet and exercise for both weight loss and maintenance. But for faster weight loss, you may have more success changing your diet than increasing your exercise. Before starting any weight loss program, talk to your doctor or schedule an appointment with a dietitian for a personalized plan.
Eating Less To Lose Weight
Everyone has a set amount of calories, or energy, they need to simply be alive. Consistently eating less than this can cause your metabolism to slow down and your body to begin preserving what it can to survive. Hunger and feeling full aren’t the only indicators of whether you’re fueling your body appropriately. Indeed, short and long-term dietary restrictions on weight and the traditional weight-loss methods of calorie cutting and deprivation may actually be a hindrance to many health goals.
Beyond calories, I’ve had countless clients come to me after trying fad weight loss diets, none of which “worked” in that any weight lost was regained once they stopped the diet. Diet culture, in general, does a good job of making people feel like failures if they don’t have long-lasting success from a diet when it’s the diet that fails us. There is little to no research showing any fad diet results in sustained long-term weight loss. This is the first thing I explain to clients so they don’t feel defeated or ashamed because they did nothing wrong.
You’re Thinking About Food All The Time
Consistently not eating enough food often results in a preoccupation with food and persistent thoughts about food and your next meal or snack. This could manifest in behaviors like perusing restaurant menus online, obsessing over food social media accounts or watching cooking shows incessantly. The association of dietary deprivation and food preoccupation was first discovered by Ancel Keys in his landmark Minnesota Starvation Experiment during World War II.
Many of the participants in the study admitted to obsessively collecting recipes and recipe books, and as the study went on, food became one of the only things they thought about. While this is an extreme example, the chronic dieting and food deprivation so prevalent in today’s culture can absolutely have a similar effect.
You’re Tired And Cranky
“Hanger” is one of my favorite terms for feeling so hungry, you are borderline angry. I’m sure this is relatable to many people, and there is some science to explain it. When you go long periods without eating, blood sugar tends to drop. If you don’t eat something to raise blood sugar, and it remains low, your ability to concentrate, be patient with others and mentally focus diminishes. Enter crankiness, which can easily be reversed by eating something. Tiredness and fatigue also go hand in hand with not eating enough, because you’re simply not providing the body with enough energy. These cues are often our body’s way of innately telling us what we really need.
You Can’t Sleep
There is nothing worse than feeling tired but being unable to sleep. This is another common result of dietary deprivation, with research roots dating back to the starvation experiment mentioned above. More recent research from eating disorders and sleep to malnourished infants and sleep further emphasizes the profound effect diet may have on our sleep cycles. What’s more, it has been consistently found that diet restoration and maintaining adequate energy intake may also restore normal sleep-wake patterns.
When your body is consistently not getting enough calories to meet your needs, the digestive tract may move food through your system more slowly to preserve energy. As a result, this can cause constipation. Similarly, not eating enough fiber — which is common when you restrict calories below your needs — can cause constipation.
Your Weight Plateaus Or Increases
When the scale won’t budge or if you start to gain weight while on a diet, the answer is not to eat even less. Instead of providing the body with less energy, perpetuating the metabolic response that fights against weight loss, the solution is often to eat more.
Start by adding a snack or two between meals and make sure to include all of the macronutrients — protein, fat and carbs. Once you’re fueling the body correctly, your weight ends up where it should be.
Why You’re Losing Muscle, Not Fat
Let’s begin with a quote:
“The reduction of energy intake continues to be the basis of…weight reduction programs…[The results] are known to be poor and not long-lasting.”
– George Bray, Pennington Biomedical Research Center
Eating less does not create the need to burn body fat. Instead, it creates the need for the body to slow down. Contrary to popular opinion, the body hangs on to body fat. Instead, it burns muscle tissue, and that worsens the underlying cause of obesity. Only as a last resort, if the body has no other option, it may also burn a bit of body fat.
Why does the body hang on to body fat and burn muscle? To answer that question, let’s look at it another way.
What does our metabolism want more of when it thinks we are starving? Stored energy.
What is a great source of stored energy? Body fat.
So when our metabolism thinks we are starving, does it want to get rid of or hold on to body fat? It wants to hold on.
Next, what does our metabolism want less of when we are starving? It wants less tissue (which burns a lot of calories). What type of tissue burns a lot of calories? Muscle tissue. So when our metabolism thinks we are starving, it gets rid of calorie-hungry muscle tissue. Studies show that up to 70% of the weight lost while eating less comes from burning muscle—not body fat!
Burning all this muscle means that starving ourselves leads to more body fat—not less—over the long term. As soon as we stop starving ourselves, we have all the calories we used to have but need less of them, thanks to all that missing muscle and our slowed-down metabolism. Now our metabolism sees eating a normal amount as overeating and creates new body fat.
In the Journal of the American Medical Association, researcher G.L. Thorpe tells us that eating less does not make us lose weight, “…by selective reduction of adipose deposits [body fat], but by wasting of all body tissues…therefore, any success obtained must be maintained by chronic under-nourishment.” It is not practical or healthy to keep ourselves “chronically under-nourished,” so we don’t. Instead, we yo-yo diet. And that is why eating less is not an effective long-term fat loss approach.
Diet to Lose Weight
No single weight loss diet works for everyone. When it comes to losing weight, you need to find a diet that fits your taste buds and lifestyle. Making a few changes to your usual intake may help you cut the calories to lose the weight and improve your health.
For example, instead of soda, drink water or seltzer flavored with a splash of juice or lemon. Use mustard on your sandwich instead of mayonnaise and swap out your bag of chips for a garden salad. Instead of meat lover’s pizza, go for plain cheese or one loaded with veggies. When plating food, make your veggies the main focus, and consider meat and grains the side dishes.
Diet vs. Exercise
According to Harvard calculations, a 70kg person (about the weight of the average Aussie woman) who runs at 10km/h for 30 minutes will burn 372 calories. Many people will struggle to sustain that level of effort, let alone keep up it up every day.
But you could achieve the same energy deficit just by cutting out cheeky daily snacks — a can of Coca-Cola (160 calories) and two Tim Tams in the evening (200 calories), for example — or by slightly reducing the portions of your dinner (a meal that averages about 800 calories) then having Greek yoghurt for dessert instead of high-end ice-cream (127 calories/100g vs 246 calories/100g).
So which sounds more do-able: a gruelling stint of exercise, or small changes to what you eat?
Mosley believes that understanding how many calories are in food, and how little of those calories are burned off by exercise, is an important lesson for those keen to lose weight — particularly because many of us are guilty of exercising and then (consciously or unconsciously) rewarding ourselves with food, thereby undoing the calories lost in the workout.
“If you are aware of how many calories you’re actually burning during exercise compared to what you’re taking in from food, then you may have the willpower to say, ‘No, I won’t have that 400-calorie muffin after all’,” he says.
“It makes you realise that to burn off all the calories you’re probably going to have to run for about an hour, or something like that.”
An important note about all this: exercise might not be the most effective way to lose fat, but that’s no excuse not to exercise.
“Exercise is emphatically not a waste of time,” Mosley says. “If you’re simply exercising to look at the scales then it may not be that great [but] there are so many other benefits.”
He offers a long list of them: exercise boosts mood; exercise increases blood flow around the body, especially to the brain (perhaps warding off dementia later in life); exercise cuts your risk of heart disease; exercise helps people who’ve already lost weight keep it off.
An upcoming episode of Trust Me also suggests exercise suppresses some people’s appetites, helping them control cravings — contrary to the belief that exercise makes you hungrier.
Mosley adds that when many people set out to exercise, they focus on aerobic exercise (aka cardio like running, jogging, swimming) and forget about equally important resistance exercise.
“After the age of 30 we typically lose between 1 and 5 percent of our muscle mass per decade, unless we do something about it,” he explains.
He adds that resistance exercise doesn’t have to be lifting weights in the gym.
“I do five to six minutes of resistance exercise at home every morning using my own bodyweight,” he says. “I simply do squats and press-ups and things like that.”
Saying “dieting is a better way to lose weight than exercise” is great. But as we all know, dieting can be really effing hard.
“The major problem with diets is that you feel deprived, and that’s why people find it very difficult to stick to them,” Mosley points out. “If you just cut out whole food groups then firstly, it’s not terribly good for you, and secondly, you’re not going to be able to sustain it.”
He believes the popular idea of a diet (“I need to cut out everything I enjoy and only nibble on slivers of poached chicken and steamed broccoli!”) is all wrong. Instead of eating less, he advises eating differently — citing the popular (and scientifically backed) Mediterranean diet as an example.
“The Mediterranean diet is changing what you eat but you’re not depriving yourself,” Mosley says. “It’s a relatively high-fat diet but it has enormous proven benefits.”
The best diet is any diet you can stick to, and people stick to the Mediterranean diet because it replaces “bad” stuff with satisfying substitutes: switching from hamburgers to oily fish, from saturated fats to olive oil, from sugary snacks to nuts.
Successful dieting isn’t about cutting everything out, but “switching to other forms of eating… broadly it’s a matter of changing what you eat as well as the quantities,” Mosley explains.
He also recommends adding extra fibre to your diet, which — like the healthy unsaturated fats in the Mediterranean diet — will help you feel fuller even though you might actually be eating less. (Click here for some high-fibre food suggestions.)
“On a Western diet you’re eating about 15g of fibre a day,” Mosley says. “If you’re eating 30-40g then you’ll feel full, you won’t feel deprived.”
The Bad Side Effects Of Food Deprivation
Imagine watching TV and seeing a commercial for a new medication. The ad tells you the medication slightly improves your vision as long as you keep yourself chronically sleep-deprived. At the end of the commercial, a quieter voice lists the medication’s long-term side effects. One of them is that your vision will become much worse if you ever go back to sleeping a normal amount.
Would you ever use that medication? Of course not. You cannot go through life tired. Its temporary benefit is not worth its long-term side effects.
Now imagine another commercial.
This one is for a mail-order weight-loss meal program that slightly reduces your weight as long as you keep yourself chronically food-deprived. At the end of the commercial a quieter voice goes though the program’s side effects. The side effects include making you much heavier if you ever go back to eating a normal amount.
Would you ever use that program? Of course not. You cannot go through life hungry. To escape the superstition of starvation, let’s dive deeper into the science of its side effects.
My favorite experiment showing the side effects of eating less took place at the University of Geneva and involved three groups of rats all eating the same quality of food.
Normal Group: Adult rats eating normally.
Eat Less Group: Adult rats temporarily losing weight by eating less.
Skinny Group: Young rats who naturally weighted about as much as the adult Eat Less group immediately after this group ate less.
If the study were conducted on humans, the Normal Group would be typical thirty-five-year-old women. The Eat Less Group would be thirty-five-year-old women cutting calories until they fit into their high school jeans. And the Skinny Group would be high school girls who fit into size four jeans without trying.
For the first ten days of the study, the Eat Less Group ate 50% less than usual while the Normal Group ate normally. On the tenth day:
The Skinny Group showed up and ate normally.
The Eat Less Group stopped starving themselves and started eating normally.
The Normal Group kept eating normally.
This went on for twenty-five days and the study ended on day thirty-five.
At the end of the thirty-five day study, the Normal Group had eaten normally for thirty-five days. The Eat Less Group had eaten less for ten days and then normally for twenty-five days. And the Skinny Group had eaten normally for twenty-five days.
Which group do you think weighed the most and had the highest body fat percentage at the end? The Skinny Group seems like an easy “no” since they are younger and naturally thinner than the other rats. Traditional fat loss theory would say the Eat Less Group is an easy “no” as well since they ate 50% less for ten days. So the Normal Group weighed the most and had the highest body fat percentage at the end of the study, right?