Part 5: Nutrition and Exercise, Body Image
Based off the book "The Science of Nutrition" by Rhiannon Lambert
What do you eat before exercising? The consensus is to eat a meal 2–4 hours before working out, where possible. An ideal pre workout meal is mainly carbohydrate with some protein and a little fat, for example, salmon, white rice, and vegetables roasted in olive oil. If you train early and don’t have the time or appetite, try a more carb-heavy meal the night before. If you’re exercising sooner, or need to top off, a snack (like toast and honey or fruit salad) 1–2 hours beforehand gives a burst of energy for fuel and is quickly absorbed. With under an hour, stick to liquids like smoothies or sports drinks. Experiment to find the optimal timing for your activity, schedule, and digestion. During exercise: Water should suffice for 45–75-minute sessions. After an hour, you may want to consume around 30g of carbs per hour for two hours, increasing to 60g per hour for the next 2–2.5 hours. Gels and sports drinks can help maintain blood sugar levels but can also contribute to stomach upset during endurance activities like distance running; practice what works for you. Carb–protein balance: Recovery foods should contain quality carbohydrates to replenish glycogen and fluid and electrolytes to rehydrate effectively. In addition, combining a small amount of protein with carbs post workout has been shown to more effectively promote glycogen recovery than carbohydrates alone. If your training is mainly strength based, or if you’re training at a high intensity, there is evidence that adding 15g–25g of protein to a post workout meal or snack can reduce muscle soreness and promote muscle repair. Otherwise, follow your food preferences, appetite, and what sits comfortably in your stomach after exercise, and eat when you feel hungry. IS IT GOOD TO BE SLIM? ‘‘Slim’’ is just one of many cultural constructs about how our bodies should look. But achieving these ideals and being a healthy weight aren’t necessarily related. Body size and shape aren’t always the best indicator of health. Someone who eats a less healthy diet and does little exercise may be genetically predetermined to have less body fat than someone in a larger body leading a healthier lifestyle. Based on current evidence, weight loss can be maintained, but a gradual process is more effective. Losing a pound or two a week allows your body to adapt and is sustainable in the long run. As babies, we are in tune with our body’s hunger signals and eat only what we need, but as we age, we’re surrounded by messaging and social pressures around food and lose this innate ability. The complex psychology surrounding our relationship with food undoubtedly plays a role in the failure of diets and can be the biggest barrier to weight loss. Research shows that restrained eaters experience more intense food cravings, heightened emotions surrounding food, and greater preoccupation with it. Likewise, categorizing foods as “good” or “bad” creates a restrictive mindset that increases food cravings and, in turn, the risk of overeating these foods when they are available. Labeling foods as treats implies they can be eaten only once earned, which increases desire. Goal setting can also have detrimental psychological effects, as veering “off plan” can prompt feelings of failure and guilt and subsequent overeating. SHOULD I COUNT CALORIES? Counting helps build awareness of our daily energy consumption. But food is more than calories, and reducing it to a number risks oversimplifying its nourishment. Unhealthy counting as well as being time consuming, calorie counting can lead to restrictive behaviors or unhealthy habits. It may be tempting to eat highly processed foods because calories are clearly displayed on packaging and easier to count, or to exclude nutrient-dense foods like oily fish and nuts purely on the basis of their calorie content. CAN I RELY ON THE SCALE? If you’re trying to lose weight, stepping onto the scale feels like a moment of truth. But the number doesn’t show what’s actually happening in your body. Your weight can fluctuate after just one meal, and over a day. We’re often heavier in the evening after eating and drinking; salt, alcohol, medication, and menstruation can also cause water retention. One study found that weight is highest after the weekend and the ideal weigh-in time is Wednesday morning before consuming anything. If you want to establish a rough base weight, use the same scale, at the same time, without clothes. In addition, overreliance on the scale could contribute to an unhealthy body image and relationship with food, and for some people it can become a crutch. What doesn’t the scale tell me? Be mindful that a weight reading doesn’t reflect how much body fat you are carrying, your overall body composition, or how healthy you are. Even if the number on the scale isn’t falling, you could still be losing body fat, gaining muscle, sleeping better, and improving your gut health. Homeostatic hunger refers to the physical feeling of wanting to eat, caused by the need for energy. Hedonic hunger describes the desire to eat for pleasure. When we smell or eat something tasty, the brain releases pleasure hormones like dopamine. We then associate that food with the feeling of pleasure we experienced, making us want to eat it again, or eat more of it than we need. Psychological and emotional factors affect the balance between hunger hormones in ways we don’t yet fully understand. Tiredness can also have an impact. The human body has a complex system of hormones that interact in myriad ways. For example, cortisol, a stress hormone suppresses appetite, but in cases of chronic stress, it can enhance appetite. It seems as we age, we lose connection with our innate hunger signals. For instance, people easily confuse thirst for hunger. Fighting against feeling hungry can do more harm than good, but it’s good to recognize and acknowledge whether your body is actually in need of fuel or if your hunger is actually for the pleasure you associate with food. If you feel tired and your stomach is growling, it’s likely your body lacks energy and you need to refuel to satiety. If this happens often, eat a little more at mealtimes, consider increasing your carbohydrate intake, or take a snack with you when out and about. If it’s hedonic hunger that you keep feeling, it’s likely you’re in need of satiation. Research suggests some types of food can be more satiating than others. A diet rich in fiber or high in protein suppresses ghrelin (the hunger hormone) effectively.
