You’re trying to lose weight, and you want to do it fast. In fact, you want those pounds gone yesterday! Sound familiar? Slashing calories might seem like a good approach when you want to supercharge your results – but don’t fall into the calorie restriction trap, as many people do. It’s simply not conducive to your goals long-term and can be disruptive to your mental and physical health.
Curious as to why restrictive dieting does more harm than good? Here are five compelling reasons to stop focusing on calorie restriction and lose weight in a healthy, sustainable manner. You’ll get the job done without harming your health or slowing your metabolism.
Restrictive Dieting: It Doesn’t Work
Calorie restriction, theoretically, should work. The first law of thermodynamics (remember physics class?) says that reducing your energy intake should lead to weight loss since energy and mass are interconvertible. If you take in more energy and don’t burn it off, the excess will be converted to mass, which in this case is body fat. Likewise, consuming less energy, in the form of calories, means your body is forced to burn stored fat to meet its energy requirements.
Sounds simple, doesn’t it? But, rarely is the human body so straightforward. You also have to consider the hormonal response to the calories you take in. Your body doesn’t respond to 200 calories of leafy greens the same way it does a 200-calorie piece of candy. The latter causes a greater insulin surge and that impacts how those calories are processed.
The insulin surge from that candy means that insulin hangs around for a while and this makes it harder for your body to access and break down fat stores. Even if you’re in a calorie deficit, insulin impedes your body’s ability to use stored fat as an energy source. Because your body can’t use stored fat as easily for energy, your metabolism slows to conserve energy.
Is calorie restriction always futile for weight loss? If you consume fewer calories than you burn off, you may lose weight shorter term. But, thanks to your body’s amazing ability to adapt to periods of starvation by slowing your metabolic rate, the weight you lose can return as quickly as you lost it. Fewer than 20% of people who lose 10% or more of their body weight maintain that weight loss.
The process by which your body adapts to calorie restriction is called adaptive thermogenesis and it stems from the interplay of a variety of hormones, including appetite hormones, like leptin and ghrelin, thyroid hormones, and stress hormones.
The end result is thermogenesis slows and your body needs fewer calories. It makes sense, doesn’t it? Your body senses a changing energy intake and makes compensations that allow it to “make do with less.” Even more disturbing is a study showing that these changes due to adaptive thermogenesis can last for years after a calorie restricted diet.
When you significantly reduce your calorie intake, you set your body up to run more slowly. Plus, excessive calorie restriction can also, without your awareness, change how much energy you expend. It’s another way your body adapts to having fewer calories to work with. You unconsciously move around less to conserve energy.
Restrictive Dieting: It Can Lead to Nutritional Deficiencies
Cut your calories enough and you could end up in a nutritional shortfall. When you cut calories significantly, it’s harder to get sufficient macronutrients, including protein, healthy fats, and carbs. Plus, it’s also harder to meet your body’s micronutrient needs as well. Restrictive dieting can lead to various vitamin and mineral deficiencies, especially if you do it long term.
Restrictive Dieting: It’s Not Good for Your Mood
In a study carried out at the University of Minnesota, a group of men lived in a dorm where they could be closely monitored for six months. During their stay, they consumed half of their usual number of calories, with the goal of losing 2.5 pounds of weight per week.
Not only did the men become obsessively focused on food, but they also experienced other stress-related signs and symptoms, including fatigue, hair loss, ringing in the ears, fluid retention, and anxiety. When you drastically cut calories, your brain constantly reminds you that you need more fuel and you become more focused on all aspects of eating. Such extreme dieting creates an unhealthy relationship with food and turns it into the “enemy,” hardly a healthy approach to long-term weight control.
Not to mention, restrictive dieting gives you less energy and motivation to exercise, and we know that exercise is an essential part of maintaining any weight that you lose.
Restrictive Dieting: It Can Cause Health Problems
Not consuming enough calories is linked to infertility in women. You need a certain amount of energy intake to trigger ovulation and if you fall short and ovulation fails, you’ll have problems becoming pregnant. Plus, extreme calorie restriction over a period of time can lower your estrogen level and contribute to bone loss. Women who restrict calories and over exercise are at particularly high risk for this. Combine calorie restriction with excessive exercise and it leads to further reductions in estrogen as well as elevations of the stress hormone cortisol. This negatively impacts immune health and can disrupt blood sugar control as well.
Restrictive Dieting: It Can Interfere with Fitness Gains
Your body needs macronutrients to convert to ATP to fuel exercise. If you don’t supply enough, your performance will suffer. Plus, along with bone loss, you’re at higher risk of muscle loss. You lose metabolically active muscle tissue. You don’t want this, and it further slows your resting metabolism. Even if you’re losing weight, you’re losing muscle mass along with fat and that shouldn’t be the goal.
The Bottom Line
Restrictive dieting is self-defeating and unsustainable. If you need to lose weight, lose it in a healthy manner, not by embarking on a semi-starvation diet. Rather than cutting back on calories, make smarter food choices – more nutrient-dense, whole foods, and less junk. Make it a plan you can live with now and into the future.
Medscape.com. “Role of Adaptive Thermogenesis in Unsuccessful Weight Loss Intervention”
Psychology Today. “Dieting Can Make You Lose Your Mind”
Am J Physiol Endocrinol Metab. 2015 Jan 1;308(1): E29-39. doi: 10.1152/ajpendo.00386.2013. Epub 2014 Oct 28.
Am J Clin Nutr. 2010 Aug; 92(2): 304–312.