IS BODYWEIGHT AFFECTED BY WHEN YOU EAT?
Here's what science knows so far.
MOST DIET AND HEALTH ADVICE is broadly based on the assumption that a calorie is a calorie (and it doesn’t matter when they’re consumed). But some research suggests that our bodies actually use calories more efficiently when consumed in the morning as opposed to the evening. This points to a strategy that could be beneficial for weight loss.
While there are many reasons for this phenomenon, one may be our circadian rhythm. This is the natural, internal process that regulates our sleep-wake cycle over a 24-hour period. Not only does our circadian rhythm make us feel tired at night and alert during the day, it also regulates the timing of the body’s processes – including digestion, metabolism, and appetite regulation – by secreting certain hormones based on what and when we eat, our physical activity and time of day.
However, this internal process can be altered by eating or exercising at abnormal times of the day. Changes to our circadian rhythm can impact our physical and mental health, and our immunity.
Given how important the circadian rhythm is for our bodies and overall health, our team wanted to know what effect it has on our metabolism. We conducted a review that examined studies in humans whose circadian rhythms had been disrupted on purpose by researchers, or because of night eating syndrome, where a person ate more than 25% of their daily calories in the evening or middle of the night.
Based on these studies, it was clear that our bodies do indeed prefer us to eat during daylight hours – in sync with our natural circadian rhythm. Most of the studies showed that intentional circadian rhythm disruption and night eating both caused changes to many important hormones that regulate appetite, energy expenditure, and glucose regulation (resulting in changes in the levels of circulating insulin, leptin, cortisol, and other appetite hormones in the blood).
Changes to these hormones could theoretically increase appetite while decreasing energy levels, leading to more calories eaten but fewer burned throughout the day. This could potentially lead to weight gain, but more research on this effect in humans is needed.
But given that all the studies were investigating different things (and so had different results), and they didn’t measure changes in energy intake, expenditure, and weight, this makes a suggested link between circadian rhythm disruption and weight gain inconclusive. However, our study does find that the body’s processes work best when you have regular sleep habits and don’t ignore your circadian rhythm.
METABOLISM AND BODY WEIGHT
Other studies have also found evidence that suggests a time of day influences energy balance and body weight. For example, eating more calories in the late evening has been linked with weight gain and obesity, possibly because of lower appetite regulation in the evening, or because late meals disrupt circadian rhythms and our energy levels – making us less likely to exercise the following day.
Eating most of your calories in the morning may also lead to greater weight loss. This weight loss seems to occur despite similar daily food intake and activity levels to those who ate more calories in the afternoon or evening. Though it’s not known why this is the case, it may be because people who miss breakfast snack more in the evening – or it could be because later food intake disrupts circadian rhythms. However, it should be noted that not all studies agree that eating most of your day’s calories in the morning leads to greater weight loss.
It has also been shown that higher levels of physical activity in people who eat breakfast (compared to those who didn’t) may contribute to greater weight loss, so long as more calories are eaten in the morning instead of the evening. Again, researchers aren’t entirely sure why, but the theory is that morning feeding gives people more energy during the day, so they may be more active. In contrast, consuming calories in the evening don’t promote activity. Calories late in the evening may also disrupt circadian rhythms, leading to overall greater feelings of tiredness the next day and reduced physical activity.
A recent study also found changes in the brain’s signals that control food reward in response to feeding time. The researchers think that eating more calories in the morning may improve body weight by reinforcing the brain’s reward centers related to food – therefore reducing overeating.
Time-restricted feeding (sometimes known as “intermittent fasting”) is another approach gaining interest. This is when people are only able to eat within a specific timeframe over the day (such as over an eight or 12-hour period). Research shows this appears to support weight loss predominantly through reducing calorie intake, likely because there’s less time to eat. Intermittent fasting may also reinforce the natural circadian rhythm by stopping late-night eating.
While there’s plenty of evidence supporting daytime eating as it’s more in line with our natural circadian rhythm, more research is needed to fully understand the effect that this has on body weight. Of course, the type of foods you choose and your portion sizes have the biggest impact on your health. But if it’s the case that eating time is linked to differences in body weight and health, then when you eat may also need to be included in dietary advice.
Je, uzito wa mwili huathiriwa na wakati unaokula? Hapa kuna kile sayansi inajua hadi sasa. MAISHA MENYAKO na SALAMA ZOTE hutegemea dhana kwamba kalori ni kalori (na haijalishi ni lini zinatumiwa). Utafiti unaonyesha kwamba mwili wetu hutumia kalori kwa ufanisi zaidi wakati wa asubuhi kuliko jioni. Hii inaonyesha mbinu ambayo inaweza kuwa na manufaa kwa ajili ya kupoteza uzito. Ingawa kuna sababu nyingi za jambo hilo, moja ya hizo huenda ikawa ni utaratibu wetu wa mzunguko wa saa. Hii ni mchakato wa ndani wa mwili ambao unadhibiti mzunguko wa usingizi na kuamka kwa muda wa saa 24. "Si tu kwamba mzunguko wetu wa circadian hutufanya tujihisi uchovu usiku na tahadhari wakati wa mchana, lakini pia unadhibiti wakati wa michakato ya mwili - ikiwa ni pamoja na kumeng'enya, kimetaboliki, na udhibiti wa hamu ya kula - kwa kutoa homoni fulani kulingana na kile na wakati tunakula, shughuli zetu za mwili na wakati wa siku. """ Hata hivyo, utaratibu huo wa ndani waweza kubadilishwa kwa kula au kufanya mazoezi wakati usio wa kawaida wa siku. Mabadiliko katika mzunguko wetu wa circadian yanaweza kuathiri afya yetu ya kimwili na ya akili, na kinga yetu. Kwa kuzingatia umuhimu wa mzunguko wa circadian kwa mwili wetu na afya kwa ujumla, timu yetu ilitaka kujua ni athari gani ina juu ya kimetaboliki yetu. Katika utafiti wa utafiti wa utafiti wa binadamu, utafiti wa binadamu ulipunguza viwango vya circadian, na kwa sababu ya ugonjwa wa kula usiku, watu waliokula zaidi ya 25% ya kalori zao za kila siku wakati wa jioni au usiku. Kulingana na masomo haya, ilikuwa wazi kwamba miili yetu kwa kweli hupendelea sisi kula wakati wa masaa ya mchana - kwa usawa na rhythm yetu ya asili ya circadian. Utafiti wa hivi karibuni unaonyesha kwamba kuharibika kwa mzunguko wa circadian na kula usiku kwa makusudi kunasababisha mabadiliko katika homoni nyingi muhimu ambazo zinadhibiti hamu ya kula, matumizi ya nishati, na udhibiti wa sukari (kuongoza kwa mabadiliko katika viwango vya mzunguko wa insulini, leptin, cortisol, na homoni nyingine za hamu ya kula katika damu). Mabadiliko katika homoni hizi yanaweza kuongeza hamu ya kula wakati wa kupunguza viwango vya nishati, na kusababisha kalori zaidi kula lakini chini kuchomwa siku nzima. Hii inaweza kusababisha kuongezeka kwa uzito, lakini utafiti zaidi juu ya athari hii kwa wanadamu inahitajika. Lakini kwa kuzingatia kwamba masomo yote yalikuwa kuchunguza mambo tofauti (na hivyo alikuwa na matokeo tofauti), na wao si kupima mabadiliko katika ulaji wa nishati, matumizi, na uzito, hii inafanya uhusiano uliopendekezwa kati ya usumbufu circadian rhythm na uzito gain inconclusive. Hata hivyo, utafiti wetu unagundua kwamba michakato ya mwili inafanya kazi vizuri zaidi wakati una tabia za kulala za kawaida na usipuuze rhythm yako ya circadian. METABOLISM AND BODY WEIGHT Uchunguzi mwingine pia umepata ushahidi unaoonyesha kwamba wakati wa siku huathiri usawa wa nishati na uzito wa mwili. Kwa mfano, kula kalori nyingi mwishoni mwa jioni kumehusishwa na kuongezeka kwa uzito na unene, labda kwa sababu ya udhibiti wa hamu ya kula ya chini jioni, au kwa sababu chakula cha marehemu kinaharibu mizunguko ya circadian na viwango vyetu vya nishati - kutufanya tuwe na uwezekano mdogo wa kufanya mazoezi siku inayofuata. Kula kalori nyingi asubuhi pia kunaweza kukusaidia kupunguza uzito. Kupungua kwa uzito kwa kawaida hufanyika licha ya kiwango cha chakula cha kila siku na kiwango cha shughuli sawa na wale ambao walikula kalori zaidi alasiri au jioni. Ingawa haijulikani ni kwa nini hii ni kesi, inaweza kuwa kwa sababu watu ambao kukosa kiamsha kinywa vitafunio zaidi jioni au inaweza kuwa kwa sababu baadaye ulaji wa chakula disrupts circadian rhythms. Hata hivyo, ni lazima ieleweke kwamba si masomo yote yanayokubali kwamba kula kalori nyingi za siku yako asubuhi husababisha kupoteza uzito zaidi. Pia imeonyeshwa kuwa viwango vya juu vya shughuli za mwili kwa watu wanaokula kiamsha kinywa (kilinganishwa na wale ambao hawakufanya hivyo) inaweza kuchangia kupoteza uzito zaidi, kwa muda mrefu kama kalori zaidi zinakula asubuhi badala ya jioni. Watafiti hawajui kwa nini, lakini nadharia ni kwamba kula asubuhi huwapa watu nishati zaidi wakati wa mchana, kwa hivyo wanaweza kuwa na shughuli nyingi. Kinyume chake, kula kalori jioni hakuhimizi utendaji. Kileo cha jioni pia kinaweza kuharibu mzunguko wa mwili, na kusababisha hisia kubwa ya uchovu siku inayofuata na kupunguza shughuli za mwili. Utafiti wa hivi karibuni pia uligundua mabadiliko katika ishara za ubongo ambazo zinadhibiti thawabu ya chakula kwa kujibu wakati wa kulisha. Watafiti wanafikiri kwamba kula kalori zaidi asubuhi inaweza kuboresha uzito wa mwili kwa kuimarisha vituo vya thawabu vya ubongo vinavyohusiana na chakula - kwa hivyo kupunguza kula kupita kiasi. Kulisha kwa muda mdogo (wakati mwingine huitwa <unk>kufunga kwa vipindi<unk>) ni mbinu nyingine inayopata upendezi. Hii ni wakati watu wanaweza tu kula ndani ya muda maalum wakati wa siku (kama vile zaidi ya masaa nane au 12). Utafiti unaonyesha hii inaonekana kusaidia kupoteza uzito hasa kupitia kupunguza ulaji wa kalori, pengine kwa sababu kuna muda mdogo wa kula. Pia, kufunga kwa vipindi vya muda kunaweza kuimarisha utaratibu wa kawaida wa chakula kwa kuacha kula usiku sana. Ingawa kuna ushahidi mwingi unaounga mkono kula wakati wa mchana kwani ni sawa na rhythm yetu ya asili ya circadian, utafiti zaidi unahitajika kuelewa kikamilifu athari ambayo hii ina kwenye uzito wa mwili. Bila shaka, aina ya chakula unachokichagua na ukubwa wa vipimo vyako vina athari kubwa zaidi kwa afya yako. Lakini ikiwa ni kesi kwamba wakati wa kula unahusiana na tofauti katika uzito wa mwili na afya, basi wakati unaokula unaweza pia kuhitaji kuingizwa katika ushauri wa lishe.